August 15, 2024
Around the world, women tend to live longer than men.
However, the sex gap in life expectancy has changed over time, as this chart shows. The data comes from combining the WHO’s Human Mortality Database and the United Nations World Population Prospects.
As you can see, the sex gap in life expectancy — defined as female life expectancy minus male life expectancy — was around 3 years in the 19th century in countries like France and Sweden. It spiked during the two World Wars, as deaths surged among young men in combat.
But it also grew gradually over the 20th century to around 7 years.
One reason for this widening gap was the rise in tobacco smoking, especially among men. Smoking increases the risk of various cancers and heart disease and leads to premature death.
Since then, as smoking has declined, the sex gap in life expectancy has narrowed in many countries.
Yesterday
Demographic trends, such as births and deaths, can be influenced by many factors. Wars or pandemics can lead to higher death rates, while lower child mortality and access to contraception reduce the number of births.
But specific cultural beliefs can also have a strong effect, as in Japan in 1966. As you can see in the chart, the UN estimates that births decreased by about 20% from 1965 to 1966.
The reason behind this drop is unusual. Children born in 1966 had the “fire horse” as their birth sign. According to astrological predictions, women born that year would bring bad fortune, especially for their future husbands.
Families who either believed this, or wanted to avoid the risk of their daughters having difficulty in the marriage market, chose not to have children that year. Couples may have abstained or used contraception, and in addition, the induced abortion rate in 1966 was significantly higher than in the surrounding years.
The next year of the fire horse is 2026. With the decline of these beliefs in Japan, fewer arranged marriages (where the birth sign might be a significant factor), and generally declining birth rates, we are unlikely to see this sharp drop in births again.
Explore more data on births and fertility in our Population & Demography explorer →
December 12
On average, Europeans consume more dairy products than people in other regions.
This chart shows the milk supply per person in each of the world’s regions. This is based on data from the Food and Agriculture Organization of the United Nations. It’s based on supply — the amount of milk available for consumption. It includes consumer waste, so it is a bit higher than the amount that is consumed in the end.
As you can see, the per-capita supply for Europe is more than twice the global average. People across Africa and Asia consume far less.
These numbers include dairy products such as yogurt and cheese, based on how much milk is used to produce them.
Explore country-by-country data on milk supply →
December 11
In 2000, adults in South Asia and Sub-Saharan Africa had, on average, fewer than five years of schooling. That’s not enough to complete primary education.
But, as the chart shows, a lot of progress has been made since then. Adults older than 25 have gained more than two additional years of schooling, a 50% increase since 2000.
Latin American and East Asian countries have also made substantial gains, starting from a higher baseline.
This data is about adults. Children today can expect many more years of schooling, showing just how much progress has been made.
Of course, simply being in school isn’t enough; kids also need to learn while they’re there. And while more years of schooling generally mean more learning opportunities, it’s important to remember that millions of children in these regions still aren’t in school at all.
Discover more insights on access to basic education →
December 10
Over the past two centuries, the global share of children enrolled in primary school has increased dramatically. In 1820, fewer than 1 in 20 children were enrolled in primary school. Today, the figure is nearly 9 out of 10.
Sub-Saharan Africa, in particular, made remarkable progress for several decades, with enrollment rising from 57% in 1985 to 77% by 2010. Yet, as the chart shows, progress has stalled in the past decade, plateauing just under 80%.
In North America and Western Europe, near-universal primary school enrollment was achieved by the mid-1900s, with rates consistently above 95% since 1985.
Explore how far the world has come in expanding access to basic education and how much further we have to go →
December 09
How has the risk of dying from cancer changed in the United States?
To understand this, we can look at national cancer death rates in the United States.
The gray line shows the crude rate, which is the rate of deaths from cancer per 100,000 people. It has risen between 1950 and 1990 and has fallen slightly since then.
However, cancer death rates rise sharply with age, and the age of the US population has increased since 1950, so we would expect cancer death rates to rise for that reason alone.
What if we adjust for the increased age of the US population?
The red line, the age-standardized rate, shows this. It shows the cancer death rate if the age structure of the US population was held constant throughout.
This shows a slight rise until 1990 and then a significant decline; rates have fallen by one-third.
This means Americans are now one-third less likely to die from cancer at the same ages as Americans in 1990.
This comes from several factors: better screening and earlier diagnosis, medical advances in cancer treatments, and public health efforts to reduce risk factors like smoking and exposure to carcinogens.
Explore this trend in other countries →
December 06
Around the world, 10 cows, 47 pigs, and 2,400 chickens get killed for meat every second.
Recent estimates suggest that 99% of livestock in the United States is factory-farmed. Globally, the majority of animals are raised on factory farms.
For many of these animals, life is short and painful.
Newborn calves are typically taken from their mothers shortly after birth, causing distress for both. Castrating and cutting off piglets' tails without anesthesia is common practice. Chickens grow so quickly that after six weeks, many struggle to stand for long and spend most of their time lying down. These animals require high doses of antibiotics to survive in poor living conditions.
There are ways to make life less harsh for farm animals. Reducing meat consumption can lessen the demand for factory farming and its associated harms. Moreover, slowing chicken growth rates or giving hens better living spaces can help reduce their suffering.
These figures are based on estimates from the Food and Agriculture Organization of the United Nations.
Explore many more charts in our Animal Welfare Explorer →
December 05
Cancer is one of the most common causes of death worldwide. In several countries, it is the most common cause of death.
But which cancer types cause the most deaths?
The map presents the most common type of cancer death among men. This is based on the cause listed on death certificates, compiled by the WHO Mortality Database. Unfortunately, many countries are not shown as they lack sufficient death registration.
Lung cancer is the leading cause of male cancer deaths in many countries, primarily driven by smoking.
In parts of Latin America, prostate cancer leads. Although it has high survival rates in richer countries, it is common and can reach late stages before diagnosis, which limits treatment options.
Stomach cancer — shown in purple on the map — is the leading cause in several Central Asian countries. It is primarily caused by H. pylori infections. In wealthier countries, infections have declined thanks to better food safety, hygiene, and antibiotics.
Liver cancer, leading in Mongolia, Thailand, and Egypt, is often the result of inflammation caused by long-term alcohol consumption or hepatitis virus infection.
Learn more about the rates of different cancers and how they have changed over time →
