Avian influenza A (H5N1), often referred to as “bird flu”, is a subtype of influenza virus that infects birds and mammals. In rare cases, humans can also be infected.
Public health experts consider H5N1 a potential pandemic threat and monitor it closely, especially through the WHO Global Influenza Programme (GIP).
Since 2003, the WHO has recorded nearly 1,000 confirmed human infections with H5N1 across 25 countries, causing more than 450 deaths.
Keep in mind that the true burden of infection is not fully known, because only a small fraction of potential cases are tested by labs to confirm whether they have influenza and to identify their strain.
I've updated our chart with the latest data from the WHO GIP (obtained via the US CDC), covering monthly reported cases since 1997. We update this data quarterly.
Data centers are the backbone of AI, cloud computing, and other digital services — and spending to build them has increased rapidly in the United States.
As of January 2026, US spending on data center construction was over $2.4 billion per month, roughly 16 times the level in early 2014.
This growth has been especially rapid since AI chatbots have become very popular, starting in late 2022. Monthly spending has nearly tripled since then.
It’s important to note that this only covers the cost of building the physical structures. Servers and other hardware inside are excluded, and they can make up a large share of the total cost of a data center.
I recently updated our chart with the latest data from the US Census Bureau. I do this quarterly, so our next update will be around June 2026.
In December 2024, passengers in California's driverless taxis were traveling around 3.8 million kilometers per month.
By the end of 2025, that figure had climbed to roughly 9.4 million — more than doubling in a single year. You can see this increase in the chart.
This data comes from the California Public Utilities Commission (CPUC), which requires companies operating paid driverless taxi services to file detailed quarterly reports on passenger distance, safety incidents, and other operational data. (Only Waymo has been in operation since late 2023.)
The reports are published on the CPUC's website, making it possible to track this fast-moving industry with publicly available, standardized data.
I recently updated this chart with the CPUC's latest quarterly report and will continue to do so each time they publish one.
As artificial intelligence advances rapidly, how are Americans’ attitudes about it changing? Are they becoming more concerned about automation, or less?
Answering these questions is harder than it might seem. Long-run, comparable opinion data on AI is rare. Most surveys only provide a snapshot at a single point in time, making it hard to track meaningful changes in public sentiment.
Two recurring surveys from YouGov, a UK-based polling and market research firm, are among the few sources that let us study these trends over time.
I recently updated both charts with the latest releases from YouGov. Both surveys are updated twice a year, with the next release expected around mid-2026.
Governments fund public services — from healthcare and education to infrastructure and defense — largely through taxation.
But how much tax revenue countries collect varies widely, as the chart shows. Here, it's expressed as a share of GDP to allow comparison across countries of different sizes.
In some countries, like Bangladesh and Ethiopia, tax revenue is less than 10% of GDP. In others, like Italy and France, it’s more than 40%.
Understanding how governments raise revenue is key to understanding fiscal policy, state capacity, and the relationship between taxation and development.
You probably use a bank account every day without thinking about it — to buy groceries, pay a bill, or receive your salary.
But for more than a billion people worldwide, transactions only happen with cash — no easy way to send or receive money remotely, and a constant risk of loss or theft.
Mobile money is changing this.
Unlike banking apps or services like Venmo, it doesn't require a bank account, smartphone, or internet. People make payments and receive deposits by simply dialling a short code on a basic mobile phone.
This technology has spread rapidly, especially across Sub-Saharan Africa, where hundreds of millions of people now rely on it.
You can see this in the chart, which I recently updated with the latest release of the Global Mobile Money Dataset from the GSM Association (GSMA). The GSMA has tracked mobile money data since 2009. The data now extends through 2024.
In our article, you can read more about mobile money and how it's expanding financial access and changing lives.
What share of income goes to the richest 1% in your country? How about the richest 10% or 0.1%? How has that changed over time?
The World Inequality Database (WID) is the leading source for answering questions about incomes and wealth at the very top of the distribution.
Standard household surveys tend to undercount incomes at the top — the wealthiest are harder to reach, less likely to respond, and more likely to underreport.
The WID addresses this by combining surveys with tax records and national accounts, giving a more complete picture of how income and wealth are distributed across the population.
Built by an international network of over a hundred researchers, the WID provides data for countries around the world, with some series going back over a century.
I recently updated 20 of our charts and multiple data explorers with the latest data.
A record 83 million people globally were living in internal displacement at the end of 2024 — forced from their homes by conflict, violence, or natural disasters, but remaining within their own country's borders.
Unlike refugees, who cross international borders, internally displaced people are often harder to track and don't show up in all migration statistics.
The data covers disaster-related displacements since 2008 and conflict-related displacements since 2009, with global coverage across all countries.
This data helps us better understand the human impact of natural disasters, conflicts, and violence — and helps NGOs and governments support those who have been displaced.
Since 1997, the price of college tuition in the United States has more than tripled. Over the same period, the price of televisions has fallen by 98%. You can see these and other trends in the chart.
This data comes from the U.S. Bureau of Labor Statistics (BLS), which compiles the Consumer Price Index (CPI) — the standard measure of inflation in the United States. It tracks the average prices paid by urban consumers for a basket of goods and services.
I recently updated our chart with the latest CPI data across 12 categories — from medical care and housing to software and toys — showing how these prices have changed over the last decades.
Safe drinking water, sanitation, and handwashing facilities are basic human needs.
Individuals who can not use safe facilities have a higher risk of disease and malnutrition, and unsafe drinking water and sanitation contribute to millions of deaths each year.
The world has made significant progress in increasing their availability and usage.
But there is still more work to do — more than 2 billion people worldwide can not use a safe drinking water source on their premises.
The ozone layer plays a vital role in making the planet habitable for us and other species by absorbing most of the sun’s ultraviolet radiation.
But, during the 1970s–90s, humans were emitting large quantities of substances that depleted the ozone layer.
This led to the creation of ozone holes at the earth’s poles, exposing life to higher levels of ultraviolet radiation and increasing the risks of skin cancer in humans.
During the 1980s, the world came together to form an international agreement to reduce — and eventually eliminate — emissions of these depleting substances.
The political agreements were very effective. Since then, global emissions have fallen by more than 99%.
The ozone holes have stopped growing and are now starting to close.
I recently updated our charts with the latest data from the NASA Goddard Space Flight Center’s Ozone Watch, which tracks the size of the Antarctic ozone hole and the concentration of ozone in the stratosphere.
