Data Insights
Bite-sized insights on how the world is changing, written by our team.
The rise of tax revenues in Southern Europe
Southern Europe demonstrates that countries can substantially increase the taxes they collect in a relatively brief period of time.
The chart shows that in 1980, tax revenues in Greece, Portugal, and Spain accounted for around 20% of their respective GDP, based on data from UNU-WIDER. This was slightly less than the United States’s 25% of GDP and much lower than Germany’s 36%.
Within a few decades, the three countries greatly increased their tax revenues. By 2021, they had almost caught up with Germany, with revenues nearly 40% of GDP. Even the 2007–2008 economic crisis only briefly interrupted their upward trend.
This shows that governments can increase their tax collection to expand public policies, even in countries where taxes were comparatively low in the past.
The age structure of populations varies widely across countries
There are many ways to examine a country's age structure. One interesting approach is to look at the age group with the largest population, as shown in the world map.
Across most African countries, the largest demographic is children younger than 10.
This contrasts sharply with Europe, where the largest age groups tend to be much older. Many European countries are most heavily populated by those in their 30s, 40s, and 50s. For example, the fifties are the largest age group in the United Kingdom and the Netherlands. In Monaco and Croatia, the most populous are those in their sixties.
If we look back to 1950, the map looks very different. Small children and teenagers were the most populous age groups in almost all countries.
Over the last 70 years, birth rates have declined in most countries, and life expectancy has increased, leading to aging populations worldwide.
Was the global decline of extreme poverty only due to China?
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 live 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 red, we see the global decline. In green, we see the decline if we exclude China from the data. In the world outside of China, 29% lived in extreme poverty in 1990 — by 2022, this share was down to 11%.
The large economic growth that lifted 800 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.
Data on suicides is lacking, especially from poorer countries
Many countries do not collect or publish national data on suicides, especially poorer countries.
Around 60% of high-income countries have shared data on annual suicide rates in a given year with the World Health Organization, but less than 20% of lower-middle-income countries do, and no low-income countries have done so since 2011.
This lack of data is partly due to an absence of vital registries — where death certificates are collected — and coroners, doctors, and legal systems to determine and record causes of death across the population.
Without this data, statistical organizations estimate suicide rates based on other data, such as surveys and data from similar countries. This is challenging because suicide is highly stigmatized in many countries and sometimes even criminalized.
The chart also shows that more countries have improved their data collection and reporting systems. With more effort to improve vital registries, we will gain a greater understanding of where and why suicides occur, who is at risk, and how to prevent this tragic cause of death.
The global eradication of polio is within reach
Polio is a highly infectious viral disease that largely affects children, causing paralysis and permanent disability; it can also lead to death.
In the early 1980s, over 50,000 cases were reported annually. This only includes cases that have been diagnosed and reported to health authorities. The true number of total cases was likely higher than 300,000 in the worst years.
The number of reported cases has been dramatically reduced in recent years. We have just updated the data shown in the chart. Last year, there were 536 paralytic polio cases worldwide.
Much of this reduction has come from global efforts toward better vaccination and improved screening and testing, primarily coordinated by the Global Polio Eradication Initiative (GPEI), founded in 1988.
Global polio eradication is possible through high vaccination rates, thorough screening and testing to detect cases, and rapid, high-quality immunization campaigns to limit outbreaks.
Read more on how our generation can eradicate polio globally →