February 10, 2025
The share of births that are twins has changed over time.
The chart shows data for France, Canada, the United States, and England & Wales in the Human Multiple Births Database.
As you can see, twin births have risen dramatically since the 1980s.
One reason is the use of reproductive technologies such as in vitro fertilization (IVF), which have made it possible for many more couples to conceive. During procedures like IVF, multiple eggs can be used at the same time to maximize the chances of a successful pregnancy, which can lead to twin births.
Another reason for the rise in twin births is that the average age of women at childbirth has risen. Older women are more likely to have twin births, even without using reproductive technologies.
Twin births are a chance event, but data shows they can also be influenced by societal changes and reproductive technologies.
Today
The Agricultural Revolution — the transition from hunting and gathering to farming — didn’t end hunger. That’s because more food didn’t mean more per person: it meant more people.
The English cleric Thomas Malthus predicted this would continue forever: food production would always be outpaced by population growth, making lasting progress against hunger impossible.
But at least since the mid-20th century, England has left mass hunger behind. How was this possible? How did English farmers prove Malthus wrong?
The chart shows one central part of the answer. For centuries, cereal yields in England — for staples like wheat and barley — were stuck at about 0.6 tonnes per hectare. That means farmers needed a plot of 100 meters by 100 meters to grow 600 kilograms of cereals per year. Hunger was widespread.
But this changed from the 17th century onward, accelerating a hundred years ago. In a dramatic transformation known as the Second Agricultural Revolution, farmers found ways to grow much more food on the same land.
Today, after four centuries of rising productivity, English farmers are growing about ten times more food on the same land than in the past. This has made it possible to increase food production faster than population growth, breaking England out of the “Malthusian Trap”.
The chart also shows that the world as a whole is changing in the same direction. Global average yields have tripled in the last six decades. Today, yields are already about five times higher than in England in the past. If yields continue to follow this trajectory, it would bring us much closer to the end of global hunger, while also sparing land for nature.
My colleague Hannah Ritchie wrote about how climate change might affect crop yields in the future →
July 14
It’s hard to imagine many things that are more terrifying than your baby contracting HIV. This is the reality for around 130,000 families every year.
Just a few decades ago, this figure was over half a million. Most of these infections were passed on from mothers who had HIV themselves.
But the introduction of anti-retroviral (ART) drugs and other interventions has meant that most infections can be prevented. If the mother takes ART during pregnancy, it dramatically reduces the risk of passing on HIV. In some cases, giving ART to the baby in the first few weeks of life can help too.
In the chart, you can see this decline in new HIV infections in children. On top, you can see the huge number of cases estimated to have been averted thanks to these interventions; they amount to almost a quarter of a million cases every year.
Explore more of our work on HIV/AIDS in adults and children →
July 11
Global trade has never been a bigger slice of the world economy. However, China, the country that most people think of as the export giant, has seen a decline in its trade-to-GDP ratio in the last 15 years.
The chart shows China’s trade in goods and services as a share of its Gross Domestic Product (GDP). In 1970, it was just 5%. Following Deng Xiaoping's economic reforms, which opened China to market forces and international trade, this figure soared to 64% in 2006. But since then, it has fallen considerably, reaching 37% in 2023. China's exports have grown in dollar terms, but its economy has expanded even faster, making trade a shrinking share of the whole.
While the 2008 financial crisis disrupted global trade, China’s trajectory also reflects the increase in domestic demand for its production. For years, Chinese officials have advocated rebalancing the economy away from export dependence and toward one driven by domestic consumption. A rising middle class now buys more of what China produces, reducing its reliance on international markets.
Explore more data on our Trade and Globalization page →
July 09
Globally, the share of the population living in extreme poverty has declined fast, from 38% in 1990 to 9% in 2024.
Some countries, however, have not made any progress against poverty. Four of them are in Southeast Africa, as shown in the chart. In Zambia, Malawi, Mozambique, and Madagascar, most people still live in extreme poverty, and this hasn’t changed in decades.
Poverty has remained high because these economies have not achieved economic growth in recent decades.
In the 1990s, most extremely poor people lived in countries that went on to have strong economic growth. Today, however, a substantial share of the poorest people live in economies that have not grown in decades. Based on current trends, this means that the world cannot expect an end to extreme poverty.
Whether or not the economies that are home to the poorest people in the world start to grow will determine whether the world ends extreme poverty.
I’ve written more about this in “The history of the end of poverty has just begun”, where I explain why economic growth is key to ending poverty →
July 07
In the late 1990s, Sri Lanka had one of the highest suicide rates in the world: three times the global average and four times the rate in countries like the United States or the United Kingdom.
The most frequent method of suicide was self-poisoning, particularly from pesticides.
But since then, suicide rates have fallen by almost two-thirds. You can see this in the chart.
The biggest driver of this improvement was the banning of particularly toxic pesticides. Two highly hazardous pesticides were initially banned in 1984, and five more were banned in 1995. This slowed the growth in suicide rates, and the trend eventually turned the corner into a strong decline.
Sri Lanka’s experience in the last few decades makes it clear that suicide rates are not “fixed” at a particular level, and there are things that can be done to reduce them.
Suicide rates have declined in many countries over decades: read our insight →
July 04
How many hours have you used electricity today? For me, it’s probably all of them — from charging my phone overnight to working on my laptop, exercising with my watch, and listening to music through my earphones. It's so normal that I can't imagine life without it.
But life without electricity is a reality for millions in Sub-Saharan Africa. This map shows the share of people with access to electricity across the region. This is defined as having a source that can provide basic lighting, charge a phone, or power a radio for just 4 hours daily.
Look at the countries in dark red: in Chad, only 12% of people have access. In the Democratic Republic of Congo — a country of over 100 million people — it's just 22%. Overall, 85% of people worldwide who lack access to electricity now live in Sub-Saharan Africa.
There are bright spots, though. Countries like Kenya, where more than three-quarters of people now have electricity, show that progress in the region is possible.
Explore more data on access to electricity →
July 02
Most of us have heard that smoking damages the lungs. The chart drives this home: in the US, men who smoke are around 21 times more likely to die from lung cancer than men who have never smoked.
But the damage doesn’t stop there: smoking also increases the risk of other cancers, including mouth, throat, bladder and pancreatic cancer, in addition to other health conditions such as chronic obstructive pulmonary disease (COPD), heart disease, and diabetes.
Why does one habit harm so many organs? Cigarettes carry a mixture of carcinogens that reach — and damage — tissues throughout the body. Smoking also injures blood vessels, fuels inflammation, and makes it easier for tumors to spread.
Because a single behavior poses so many risks, cutting smoking rates has been one of the most powerful tools to save lives and improve public health.
Explore more data and research on smoking on our dedicated page →
