On BBC Sounds, there are podcasts to help you look after your body and your mind from increasing your immunity to feeling more confident or tips on how to focus. Sorry, what were you saying? If it matters to you, it matters to us. Feel good inside and out with What's Up Docs and Complex with Kimblee Wilson. Listen on BBC Sounds. Hello and welcome to this special edition of More or Less, the show that likes to thoroughly investigate and challenge the numbers in the news and in life. I'm Tim Harford. This week we're doing things a little differently to celebrate the end of one year and the start of a new one. We're bringing you a slew of interesting numbers from 2025, which tell us something about our world that you might not already know. For those of you who are familiar with our podcast, you'll have heard our numbers of the year format before. Here, we introduce it to our Radio 4 audience with a new set of numbers. We'll be looking at the number of women in space, the average amount of time spent on social media, how much do we spend on big infrastructure projects, and many more. But first, which of you tech geeks out there knows what Moore's Law is? Find your answers down on a piece of paper and I'll leave you to mark your own work as we hear about our first number from the economist's science writer, Tim Cross. My number of the year is 208 billion, which is the number of transistors, tiny little electrical components, that NVIDIA, a big chip maker, can cram into each and every one of its blackwell GPUs. So a huge number of transistors on a computer chip. Why is this important? It's impressive because it's sort of the culmination of more than 50 years of progress in designing computer chips. And computer chips are the things that power pretty much everything in the modern world. That particular chip is designed partly to display whittly graphics in video games, but also to power the AI models that are the hottest new technology of the last 10 years. Companies don't always publicise how many transistors they put on their chips, so we can't know for sure. But that 208 billion number must be close to the highest number of transistors that anyone's ever crammed into a computer chip at any point. And this fascination with the number of transistors you can fit on a chip has been going on for 60 years. Introducing Moore's Law. A chap called Gordon Moore, who was one of the founders of Intel. In 1965, he made this sort of observation about how quickly computing was progressing. Computers had started out as these enormous machines that filled rooms and they were powered by these enormous glass valves. And over time, people found ways to shrink the machines. So transistors are essentially the sort of technological sequel to those valves that computers started with. And the best way to think about them is they're essentially a little electronic switch. So when the transistor is on, current can flow through it, and when the transistor's off, it can't. The easiest way to think of it is as essentially just a pile of switches. Some of them are on, some of them are off, and that exact arrangement of ones and zeros, you know, that's a computer program that you're running. What Moore observed was that roughly every two years, the number of transistors you could get into a chip would roughly double, and that roughly means that the chips would get twice as good. So it's less of a law, more of a prediction. This observation of something has turned into a bit of a self-fulfilling prophecy. So all these computing companies like Intel took this observation and ran with it, and Moore's law became essentially the sort of guiding principle of progress for the entire industry. And the pace of change is staggering. If you go back to 1971, Intel released a chip called the 4004, which was the first real sort of microprocessor, the first computer on a chip. They had 2,300 transistors in it, and the gap between them was sort of roughly the size of a red blood cell. And what that means is if you had a sort of decent quality optical microscope at home, you could stick it under the microscope and you'd be able to see the individual transistors. These days they've become so small that they're invisible. The transistors are much, much smaller than the wavelengths of light that humans see in. But this doubling effect can't go on forever, surely? We're going to start bumping against limits as to how much smaller you can make things. Moore himself realised this. Ever since he first made his prediction, there's been a cottage industry in the computing world of trying to work out when we'd sort of finally run out of doublings. It is slowing down. The benefits you get from each doubling aren't as big as they were, and the cost to do it is becoming higher and higher. I mean, Jensen Huang... That's the CEO of NVIDIA. He has said publicly that Moore's law is dead. There are a few reasons why chips can't double in computing power as they have done previously. If you keep shrinking something and shrinking it and shrinking it and shrinking it, eventually you run out of atoms to make it from. Not only that... All these data sensors which are full of these chips, you know, heat management is sort of one of the biggest problems. It's not all doom and gloom. They're working on new ideas all the time to manage these problems. The most straightforward one is that if you can't make the individual chips better at the same speed you used to be able to, why not just throw more chips at the problem? And this is essentially how AI works and it's why you see this demand for sort of ever bigger and more powerful data sensors. And there are other avenues to explore too. People are looking at instead of computing with electrons, what if we can do some of our computing with photons, with light rather than electricity? And one of the big advantages there is that you generate much, much less waste heat. So there are all these kind of ideas in play for keeping things going, but none of them are really quite ready for prime time yet. Tim Cross of The Economist. And now for our next number, brought to you by... I'm Caroline Steele. I'm a science broadcaster and journalist and I present crowd science on the BBC World Service. My number is six. So six is the number of women that were in the largest all-female space crew in April 2025 this year, which you might have heard about. It was the Blue Origin Flight. A six-woman crew has returned to Texas after an 11-minute rocket flight lifted them 100 kilometres to the edge of space. The American singer, Katie Perry, could be heard cheering as the Blue Origin rocket... And one of the women was Katie Perry. People had been saying this was the first ever all-female space crew, but that's not technically correct because there was a solo woman who in 1963 went into space on her own. That was Valentina Tureshkova, a Soviet cosmonaut. That was technically an all-female space crew, but this is the largest one, six. Yes, although Valentina Tureshkova was in the Soviet Air Force, whereas Katie Perry is a pop star. So some people see this as a bit of a gimmick. Although this mission has been criticised for fair reasons, it does kind of highlight the difference between the number of men and the number of women in space. And it's been traditionally such a male-dominated field. And although the privatisation of space doesn't make it easier for everyone to go into space, it has been making it easier for women to go into space. And we're seeing this kind of big gap slowly closing over time. So hopefully we will catch up. And this is the more serious point. Only in 2024 did we reach the heady figure of 100 women who'd been into space. There had been over 100 men in space in the early 1980s, so we're quite far behind, but we are playing catch-up. Thanks to Caroline Steele. Now we turn to John Byrne Murdoch, columnist and chief data reporter at the Financial Times. My number of the year is 8%, which is the decline in the average amount of time people are spending on social media per day since 2022. This is an average from a global survey covering dozens of countries. So 8% is a 12-minute reduction. Two, three years ago, the average person was spending two and a half hours or two hours 31 minutes to be precise per day on social media. That is now down to two hours and 19 minutes per day. The key thing we're talking about here is time spent on social media. And historically, that's just been going up and up. There was some bumping along in 2020 and 2021, but since then, we've seen a very clear decline. Given the research that suggests that heavy and rising use of social media may have had detrimental impacts both on some individuals and on some parts of society, I think if we are now seeing that this trend is going into reverse, it's going to be really interesting to see what second order effects come from that. How did this survey work? So this was a study from an online digital data company called GWI. And they survey dozens of countries around the world. A total of about 250,000 people each quarter are asked how much time they're spending doing various digital activities. The range of countries is everything from your UK and US down to countries like Brazil and Argentina, the Philippines, even Ghana. And so there's real global coverage here. And one of the very interesting things here is the fact that that trend of a decline in younger people or a decline overall is not universal. So on average across the globe, we get that 8% decline. But in Asia and Europe, that decline is most pronounced. In fact, the UK is on the lower end of the spectrum with on average one hour 37 minutes spent on social media in 2025. In 2024, we were at one hour 49 minutes. So that's over a 10% decline. Whereas in North America, for example, we're not seeing any decline at all. And indeed the amount of time people are spending on social media each day in the US and Canada is continuing to rise. The US and Canada bucking the global trend then. And how are different age groups behaving around the world? This is where we see one of the interesting things, which is that the decline in usage among young adults or people aged 16 to 24 has been steeper. So there we see an 18 minute reduction rather than the 12 minute average. Whereas for the oldest people those aged 55 to 64 in these surveys and indeed older, we are not seeing that decline just yet. So young people were the first to adopt these apps, to lean into them and the first to peak and then come back down. Slightly older adults have also started to decline but are less far into that decline. Whereas among your 50 and 60 somethings, the sort of adoption of these platforms is still rising. So it's almost like a sort of epidemic working its way through the population. But why are we seeing a decline? John has a few thoughts. One possibility is that it's a tailor's orders time in terms of young people are the first to think something is cool and then the first to decide it's not cool anymore, especially if you start seeing your parents or even grandparents doing it. There are other theories, for example, the perceived quality of these apps and time spent on it is deteriorated. So if you think about what it is to use social media in 2025 compared to say 2015, it is quite different. It used to be much more about checking in with one's friends, talking about what you've been up to. It's now a lot of passive scrolling through content from people you've never met and may never meet. So lots of things that could be plausible explanations here for what we're seeing. So perhaps the purpose of social media has shifted from social connection to entertainment consumption, which has resulted in an overall desire to spend less time on the socials. So does John think social media usage has peeped? I think social media has currently defined, so your TikToks and your Instagrams, I think we probably have, yeah. John Byrne Murdoch. From internet consumption to energy creation, we are going nuclear on our next number of the year. I'm James O'Malley. I'm a writer. I'm the co-host of the Abundance Agenda podcast and my number of the year is 38 billion. So 38 billion pounds is the cost of Sizewell C, the new nuclear power station that's just about under construction in Suffolk. And that's quite a lot of money. But of course a nuclear power station is going to be expensive to build. Why is this noteworthy? So when it was first proposed, I think it was proposed to cost around 20 billion pounds, but since then the costs have been revised and revised upwards. So the cost increases, a number of factors. It's simply the passage of time and inflation, it's supply chain costs and changing economic circumstances. But I think one of the really key drivers of this is the way we plan and design big mega projects like this in Britain. And it's basically a regulation thing. It's when someone wants to build a nuclear power plant, you think that sounds like a good idea. And then you think, well, we need to do a safety review and an environmental review. And you do all of these good, useful things that no one's going to object to in their own terms. This all adds up to this really big figure in almost like a one way ratchet, which is how we get into this sort of mess. But these regulations are in place to protect the environment and the people in the areas around these projects, right? So I'm not opposed to all regulation. I think we just need to have more sensible regulation. A lot of the problem is, especially with a lot of these things around building, is that the regulations haven't been designed from above as one system. It's that they've evolved over the years. So things have just been bolted on and bolted on. So all of these different reviews and checks and other things, nobody has taken a step back and said, what are we actually trying to do here? And what are we actually trying to solve? But ultimately, if we can actually build this thing, it will be a really good thing for Britain. It will provide 7% of our electricity that we're going to need if we're going to have electric cars and we're going to decarbonise and so on. Never fear. There may be some changes on the horizon. In the government's new planning reforms, which are currently going through, they're changing nature regulation. It used to be that when you had a mega project, each mega project or each project of itself, each building project would have to mitigate its own environmental circumstances. And that's how we ended up with HS2, creating spending £100 million on a bat tunnel. For those of you who may not remember, a colony of rare bats was found living near Calvert in Buckinghamshire next to the line where they wanted to build track. To protect the bats, they are in the process of building a bat tunnel at the cost of £100 million. This is one of 8,276 consents that HS2 have sought from public bodies in order to build HS2. It isn't just bats. The building of the Hinkley Sea Nuclear Power Station involved hundreds of millions of pounds being spent on measures to protect fish. These costs something like a quarter of a million pounds per fish saved. To avoid doing things like this, the government is now suggesting... Well, why don't we just have a separate pot of money which every sort of building project pays into. So it's the same amount of money that's being spent. And we can actually spend it in a more sensible way to actually achieve the aims we want. James thinks the UK easily gets bogged down trying to get big projects off the ground. I think it really represents a major challenge we face as a country and that is our inability to build things. So £38 billion is a lot of money to spend on a nuclear power plant. But it's illustrative of how all of these mega projects, whether we're building roads, railways or anything else, just the cost becomes absurd. Eisenbard Kingdom Brunel must be spinning in his grave. Genuinely though, how can we be more Eisenbard? We used to be really great at building things. We were the first country in the world to build nuclear power stations. And ultimately, if you look at a lot of Britain's problems now, we don't have the infrastructure we need to be a 21st century economy. We need to be building things. We need more energy. We need more power plants. We're creating electricity. We need more railway connections and transport connections so that businesses and people can get around more easily. We need to build our way out of Britain's economic malaise. we've just sort of forgotten how to do it. James O'Malley, and to continue in the vein of building things. I am Hannah Ritchie and my number of the year is one trillion. So that's the number of watts of installed solar power that China surpassed this year, which is equivalent to what we'd call one terawatt. A terawatt sounds like a big number, but looking at installed solar power can also be a bit misleading when we consider how much power is being used. So first, why does Hannah think it's an important number? I think it really signifies how quickly solar power has been built out globally, but actually how much China is now dominating and really rapidly moving on solar power. Now, one trillion watts of solar power produces about 1,800 terawatt hours. But to give some context of how big that number is, India in total uses about 2,000 terawatt hours, right? So the solar output from that one trillion watts of solar is almost equivalent to the total electricity generation of the whole of India from all sources. Suffice to say that if you've installed almost enough solar capacity to run India, the world's most populous country, then you have installed a lot of solar. Solar photovoltaics have followed a learning curve. The more the world makes solar panels, the cheaper they get, and of course, the cheaper they get, the more people want to buy them. There's a huge boom in solar panels going on roofs and huge solar farms across China soaking up those rays. However, China's electricity demand is also growing, so can they build renewables fast enough to meet additional demand for electricity and also push coal and fossil fuels out of the electricity mix? This looks like it could be the first year where it's basically built enough to cover all of that additional electricity demand. I mean, to give some context on how much China's electricity is growing, it's adding about a UK-sized grid every single year to its electricity demand. And actually, the fact that it's now meeting all of that additional demand from new solar and wind actually speaks to the fact of how much and how quickly they're now deploying these sources. So is China getting most of its electricity from solar energy? Solar is around 10% of electricity demand. Some more of that comes from wind, some more of that comes from nuclear and hydro, but it's important to note that still China's electricity mix is still relatively dominated by fossil fuels and primarily coal. Although this share of electricity coming from coal has been decreasing over time as these new sources have increased. How does this compare to the UK? So the UK has about 1.5% of the installed solar capacity as China. Of course, the population of China is much lower than the UK, so you might not expect those numbers to be comparable, but even when you adjust for population, China has around three times as much solar power as the UK. People might point out that the UK is not a particularly sunny place, right? So we actually tend to do a bit better on wind and actually offshore wind is a really, really key and growing source for us. The UK has had very high carbon emissions for a long period of time and we're actually now dramatically reducing those emissions. We have roughly halved domestic emissions over the last few decades, whereas China has very much been on this growth trajectory. What's perhaps interesting is that when you compare what now carbon emissions per person between China and the UK were now roughly equal. So we're kind of reaching this kind of crossing point where China's emissions per person are very, very similar to the UK's. Thank you, Hannah Ritchie. Her latest book is Clearing the Air. And finally, my number of the year for 2025 is zero, which is the number of New Year's resolutions many people managed to keep last year. Can we do better and be smarter about our resolutions? Well, to help me think about that, I'm joined by Professor Katie Milkman. She's the author of How to Change, a Science of Getting from Where You Are to Where You Want to Be. So I'm curious as to why we make resolutions on the 1st of January and whether they might not be equally well made on the 15th of May or the 9th of October. They would be equally well made on any other day, but we have a really fascinating tendency to think about our lives, like we are characters in a novel. And as though there are chapters in that novel with break points, every chapter break gives us a sense of a new beginning and a fresh start. And January 1st is a major chapter break. So we don't think of time linearly. Instead, we see ourselves on January 1st as different from the person we were in that last chapter in the year before. And we can say that was the old me who didn't get in shape. That was the old me who didn't have my finances in order. And this is the new me and things are gonna be different this time. So I guess the next step of the question, I'm planning to make some resolutions on the 1st of January because I'm a conventional minded person. What do we know about either the kind of resolutions I should make or the way I should phrase those resolutions or the way I should pursue my goals in order to ensure that I keep my resolutions? You've written a whole book on this, you've run a lab studying this. What are your top tips? The first thing you need to do is set a concrete, clear, measurable goal that's gonna push you to do something a little more ambitious than you've been doing already, right? If you already walk 3,000 steps a day and you wanna get fit, you don't wanna set a goal of walking 3,000 steps a day. You need to push yourself above and beyond what you're already doing. The goal should feel like a little bit of a stretch, but it shouldn't kill you, right? If you're walking 3,000 steps a day, the goal shouldn't be 20,000 because you're not gonna achieve that. It should be concrete and measurable. And ideally there's some step you can take, at least weekly, if not daily, that is going to be clear to you that you can plan when you're gonna do it, where you're gonna do it, and how you're gonna do it. A lot of people would just go, oh, I'm gonna take up running. I always find it doing running, I'm gonna take up running. And actually you're saying, no, set a distance, set a time, and make a plan. Yeah, that's the boring stuff, but those are critical for steps in order to have a decent goal. And then there's some interesting stuff that we've learned how you can successfully pursue these goals once you've set your plan, is that you need to make sure that you're gonna enjoy doing it. And it turns out if you don't like what you're doing, if you get on the maximally punishing stair master each time you visit the gym and you dread it, you will not persist. And persistence is the key to goal pursuit. I actually have studied one specific way of doing that. Actually I've studied a couple of ways of doing that that I think can be helpful for people to have in mind as they're thinking, oh, okay, thanks, I should make it fun, but I actually do hate working out, so how will it be fun? We have done some research on a tool that I call temptation bundling. So in my case, this morning, before I came into work to have this interview, I hopped on my elliptical at home and I watched an episode of The Morning Show while I exercised, and I only get to watch that very fun TV show, highly recommended. But I only am allowed to watch that TV show while I'm exercising. So I look forward to my workouts because it's when I get my hit of entertainment and time flies while I'm exercising because I'm distracted. In my research with collaborators, we have shown that giving people the idea and the tools to allow them to temptation bundle so that there's something, some entertainment source that they enjoy and look forward to, that they only get to enjoy at the gym, for instance, it significantly increases exercise reliably over time. And you can temptation bundle in lots of other settings too. It's not just about exercise. That's just one of the places where my team has studied it. Yeah, I like the idea of temptation bundling. It's kind of a commitment device, but it's kind of rather than saying, I'm gonna punish myself if I don't fulfill my goal, if I don't pursue my goal, you're basically making the goal itself fun, which ties into your earlier point. We also have a research study we did a couple of years ago with exercise where we told people to sign up for our program to help them build gym habits, with a friend, and then we randomly assigned them to get paid for visiting the gym, either regardless of whether they came at the same time as their friend, or they could only earn the money when they showed up at the same time as their friend, or within 30 minutes. And what we actually found there is that people exercise 35% more in the group where their pay was contingent on showing up with a friend, which is very counterintuitive to economists who would say just pay directly for the exercise that's the most straightforward incentive for the behavior you're trying to motivate, but it's more effective for two reasons. One, people enjoyed their workouts more with their friend, and second, they felt accountable to someone, and accountability is another tool that we can use to motivate ourselves to achieve our goals. It could also be temptation bundle, or it could be do it with a friend, tandem goal pursuit makes us enjoy our goal pursuit more. Thanks to Professor Katie Milkman of the Wharton School at the University of Pennsylvania. And if you're looking for something to do when you're fancy a challenge over Christmas, you can take the Open Universities Statistics Quiz, search for the BBC more or less website, and follow the links to the Open University. That is all we have time for, but we'll be back again next week with something special for you. A whole week of more or less every single day, what a way to start 2026. We've been asked by the good people at Radio 4 to take a long, hard look at the state of the nation with our BD, more or less I. There's going to be sex, there's going to be drugs, there's going to be Madeline's assumption on a pretend desert island. Well, okay, not sex and drugs, fertility rates and the economics of the pharmaceutical industry, but the last bit, Madeline's assumption, that's actually happening. Tune in every day next week from 9 a.m. to hear more or less do the stats of the nation or catch up at your leisure on the more or less feed on BBC sounds. Until then, goodbye. Hello, I'm Robin Inch. Sat next to me is Brian Cox, but I don't want him saying anything yet because I am so excited by our new series of Infant and Monkey Cage, where we're talking about timekeeping, brain computer interfaces, fusion, we're talking about the romantic and sexual behaviour of monkeys and clouds, but most importantly, Brian, what else are we talking about? Eels. We are, aren't we? Eels is one of the most fascinating programmes, if not the most fascinating. Eels. I don't want to talk about anything else, to be honest. So, basically, there's new series of Infant and Monkey Cage, but on Brian Cox's advice, don't listen to any of them, apart from the episode about Eels. It's because we don't know much about them. Don't tell them that. Listen first on BBC Sounds.
