Growing up in the United Kingdom in the 1990s and early 2000s, almost all the eggs in our supermarket came from battery hens, those raised in small wire enclosures.

The living conditions in these cages are terrible. Birds get the space equivalent of an A4 sheet of paper. They don’t have the room to carry out their natural behaviors, such as nesting, perching, or dust bathing.

That has changed in recent decades. You can see this in the chart, which shows the conditions under which eggs are produced in the UK. Free-range eggs have increased from just 10% to 75%.

The use of caged hens has fallen, and the types of caged enclosures have also changed. Battery cages were banned in 2012, so legally, all cages since then have been “enriched” ones, which provide slightly more space.

Still, these do not give hens the freedom and room they’d have in barns or free-range farms. Studies suggest that moving hens from enriched cages to cage-free systems reduces the time they spend in pain by more than half.

And given that most eggs in the UK are now free-range, it’s possible to reduce this pain even further.

The increase in the world’s population is not exponential. The global population is growing, but the growth rate has declined since its peak six decades ago.

The chart shows the annual rate of global population growth according to historical estimates and projections from the UN World Population Prospects.

The growth rate peaked in 1963 at over 2% per year, and since then, it has more than halved, falling to less than 1% by 2020.

The UN demographers expect rates to continue falling until the end of the century, eventually leading to negative growth rates and a shrinking global population.

A person’s access to doctors depends heavily on the income level of the country they live in.

High-income countries have around ten times as many doctors per person as low-income ones. You can see this in the chart, which shows the number of medical doctors per 1,000 people.

The global average is around 1.9 doctors per 1,000. Low-income countries have around one-fifth of that figure.

These figures include generalist physicians and specialists.

Chronic malnutrition in early childhood can slow development and growth, leaving children shorter than expected for their age. That’s the focus of the chart: the share of children under five who are stunted, meaning they are much shorter than expected for healthy growth.

The consequences of stunting persist beyond childhood, affecting both physical health and cognitive development.

Guatemala has one of the highest stunting rates in the world: almost half of children younger than five are stunted according to survey estimates published by the World Health Organization.

Guatemala’s rate is the highest in its region, by far. In the chart, you can see it compared to a selection of other nearby countries – its rate is twice that of Haiti, the next-highest country and a much poorer one.

My colleagues Hannah Ritchie and Tuna Acisu recently wrote about what countries with high stunting today can learn from Japan. Over the 20th century, Japan reduced childhood stunting from over 70% to under 5%, and the decline from around Guatemala's current level to under 5% took place within a generation.

In the thirty years since I was born, fertility rates in my country, the United Kingdom, have not changed much. In 1993, the fertility rate was 1.8 births per woman. Thirty years later, it had dropped only slightly, to 1.6 births.

Elsewhere, the change has been much more dramatic; fertility rates have dropped sharply and are now similar to those in the UK.

You can see this in the chart, which shows the change in fertility rates from 1993 (in blue) to 2023 (in red). In Qatar and Iran, rates dropped from almost 4 births per woman to 1.7.

Fertility rates have fallen a lot across Asia and South America, too — Malaysia and Colombia are two examples (my colleague Esteban previously wrote about the latter). This marks a much faster demographic transition than many countries experienced historically.

Convergence isn’t the whole story, though. Here, I’ve picked countries with fertility rates that are similar to the UK’s today. But some have fallen far below these levels: in Chile and Thailand, the fertility rate was 1.2 births per woman in 2023, and may have fallen even further.

Five years ago, almost no one in Latin America bought an electric car. Today, the situation is different: electric cars now make up a meaningful and fast-growing share of new car sales.

The chart shows this trend across several of the region’s largest car markets, alongside the US for comparison.

The data tracks the share of new passenger cars sold that are electric, which includes both fully battery-electric cars and plug-in hybrids.

In five years, Colombia went from nearly zero to 10%, catching up to the US.

In other countries in the region, adoption took off a bit later, but is now rising fast too. Mexico, for example, went from 2% to 7% in a single year (2024–2025).

An important part of this reflects policies. Many Latin American countries, like Colombia, offer tax breaks and other incentives for buying electric cars.