The Netherlands was the first country to legalize same-sex marriage in 2001. Since then, almost 40 other countries have followed suit.

You can see this in the chart, based on data from Pew Research. By 2025, same-sex marriage was legal in 39 countries.

Last year, two countries were added to the total. Thailand became the first country in Southeast Asia to legalize same-sex marriage, and a same-sex marriage bill also took effect in Liechtenstein.

The share of the world population living in extreme poverty has never declined as rapidly as in the past three decades.

The decline in China was particularly fast, and given that one in six people in the world lives there, we’re often asked whether the decline in global poverty was only due to the decline in China.

The chart shows the data that answers this question. In blue, we see the global decline. In red, we see the decline if we exclude China from the data. In the world outside of China, 33% lived in extreme poverty in 1990; by 2025, this share was down to 12%.

The large economic growth that lifted 940 million Chinese people out of extreme poverty since 1990 was a major contributor to the global decline in poverty. But the non-Chinese world also achieved a very large reduction.

It is not true that the global decline in poverty was only due to China. Extreme poverty has declined in China and the rest of the world.

Forty years ago in Japan, two babies were born for every person who died. Twenty years ago, these numbers were equal. And today, the ratio has reversed: one baby is born for every two people who die.

In the chart, you can see this change in the number of births and deaths over time.

Since deaths now greatly outnumber births, and because immigration is low, Japan’s population has started to shrink.

Debates over whether religion is booming or dying are common. What does the data say?

Most countries lack long-term data on religious identity, but results from the Pew Research Center offer insights into changes over the decade from 2010 to 2020. (Unfortunately, 2020 is the most recent year for which we have comparable global data.)

At a global level, there was barely any change. The share of people identifying with any religion dropped by just one percentage point, from 77% to 76%.

But religious affiliation did drop significantly across many countries in Europe, the Americas, and Oceania. You can see this drop for a selection of countries in the chart.

In Australia, rates dropped from 75% to 58%. In the United States and Chile, the percentage has decreased from roughly 85% to 70%.

So while religious affiliation is stable in many parts of the world, this data shows religion is becoming less prominent in others.

Note that this data is based on self-identification with any religion; it doesn’t tell us about changes in practices or rituals, such as prayer or attending services.

This chart shows one way to compare automated manufacturing across countries — it plots the number of robots per 1,000 manufacturing employees.

The chart shows very large differences between countries. South Korea stands out, with more than one robot for every ten manufacturing workers.

Singapore comes second, and China ranks third, close to Germany. The United States sits in the middle, close to the European average, below Switzerland, Denmark and Slovenia.

This perspective shows industrial robot adoption in relative terms. In another Data Insight, I looked at robot adoption in absolute terms. From that perspective, China stands out by a large margin: it’s a large economy with a huge manufacturing sector, and it has by far the largest stock of industrial robots.

Much of this expansion has happened recently: China’s annual installations increased 12-fold over a decade, helping it catch up to South Korea in terms of robots per worker.

Most people in the world are religious. When asked whether they identify with any religion, three-quarters of respondents choose one.

But in the chart, you can see huge differences in rates of religious affiliation across the world. In some countries, such as India and Pakistan, it’s almost universal: almost everyone identifies with a religion.

The opposite is true in China, where just one in ten people does. Several countries in East Asia, in particular, have particularly low rates of religious identification compared to other regions.

This doesn’t necessarily mean these populations hold no religious beliefs; they may still engage in activities that can be considered religious or spiritual, even though they don't describe themselves as belonging to any one in particular.

It might seem odd that countries would agree to import plastic waste from other countries, but many do so for the cheap materials or to feed specific manufacturing processes.

Environmentally, the trade in plastics has often been a concern, as it allows rich countries to effectively “dump” waste on poorer countries with weaker waste management systems.

The good news is that trade in plastic waste has fallen by more than two-thirds over the last decade. You can see this reduction in the chart.

China has been the biggest driver of this. It was once a large importer, but after a steep decline in trade in 2016 and a ban in 2018, many countries lost their largest export market.

In 2024, around 5 million tonnes of plastic waste were traded worldwide. For context, that is around 1% of the total plastic waste generated. What’s perhaps surprising is that most trade is now between high-income countries, which reduces the risk that this waste leaks into the environment.

Industrial robots are rapidly becoming a common part of manufacturing in some countries. The chart here shows how many new ones are installed each year in the industrialized countries for which we have available data from the International Federation of Robotics (IFR).

In this dataset, industrial robots are defined as automatically controlled, reprogrammable, and multipurpose machines used in industrial settings. The data covers only physical industrial robots, not software or consumer technologies.

The chart shows that in 2011, China, the United States, Japan, Germany, and South Korea were all installing similar numbers of these robots. However, in the decade that followed, the paths of these countries diverged. By 2023, annual installations in China had risen to 276,000 robots, a twelvefold increase.

Over the same period, installations in the United States, Japan, Germany, and South Korea also increased, but much more slowly: none of them even doubled. The United States, which saw the second-largest rise, went from 21,000 new installations in 2011 to 38,000 in 2023.

These figures refer to new robots installed each year; that is, annual additions to the existing stock of robots. The IFR also publishes data on the total number of robots in operation, and by this measure, China also had the largest installed base, at around 1.76 million robots in 2023.

Relative to its large manufacturing sector, China’s stock of robots today does not stand out – but the data here shows that this is changing quickly.

Most of our work on war and peace focuses on the people killed directly in the fighting. But war has many other costs: it worsens people’s health, leaves them without work, and pushes them out of their homes.

The chart shows this for the civil war in Syria. Since the war began in 2011, more than 400,000 people have been killed in the fighting. At the same time, annual deaths increased as more people died from other causes. Young children were especially affected: estimates suggest that the number of annual child deaths more than doubled.

The war has also forced millions of people to leave their homes: in total, more than seven million are displaced within Syria, and almost as many are refugees elsewhere.

It also became much harder for people to make a living. Average living standards, measured by GDP per capita, have more than halved since the war began. As a result, poverty and hunger have risen sharply.

These numbers come with uncertainty because conflict makes it hard and dangerous to collect data.

This shows that to understand the costs of war, we need to have a broad perspective and see its impacts on health, displacement, and living standards.

Three-quarters of people worldwide say they are religious. But rates of religious identity can vary a lot across countries, and so do the particular religions people follow.

In the map, you can see the most common religious affiliation for each country. This can include the “unaffiliated” who do not identify with any specific religion. This data is sourced from the Pew Research Center and is based on how people describe their own identity, regardless of their particular practices or beliefs.

As you can see, Christianity is the most common across much of Europe, the Americas, and Sub-Saharan Africa. Islam is the most common across North Africa and the Middle East, while Hinduism and Buddhism dominate across much of South Asia.

In East Asian countries such as China, Japan, and South Korea, the religiously unaffiliated are the biggest group. That doesn’t mean these populations hold no religious beliefs; they may still engage in activities that can be considered religious or spiritual, but they don’t describe themselves as belonging to any one in particular.

William Foege, who sadly died this week, is one of the reasons why this map ends in the 1970s.

The physician and epidemiologist is best known for his pivotal role in the global strategy to eradicate smallpox, a horrific disease estimated to have killed 300 million people.

Despite the world having an effective vaccine for more than a century, smallpox was still widespread across many parts of Africa and Asia in the mid-20th century.

Foege played a crucial role in developing the “ring vaccination strategy”, which focused on vaccinating people around each identified case, rather than attempting a population-wide vaccination strategy, which was difficult in countries with limited resources.

This strategy, combined with increased global funding efforts and support for local health programs, paved the way: country after country declared itself free of smallpox. You can see this drop-off through the decades in the map.

The disease was declared globally eradicated in 1980.

William Foege and his colleagues’ contributions are credited with saving millions, if not tens of millions of lives.