Battery prices have fallen more than 99% in the last three decades

In 2015, every country in the United Nations agreed on the same 17 Sustainable Development Goals for 2030 — among them, ending extreme poverty everywhere, getting every girl and boy through primary and secondary school, and bringing safe drinking water to every household. The UN tracks progress on all 17 in one place, the SDG Indicators Database.

The UN collects the numbers from the agency responsible for each subject — the World Health Organization for health, the International Labour Organization for work, etc. — then publishes them against definitions every country has agreed to. A household counts as living in a slum, for instance, if it lacks any one of five things: improved water, sanitation, enough living space, durable housing, and secure tenure.

The framework covers 234 indicators across 274 countries and territories, and some series reach back to the 1960s. We publish this data in our SDG Tracker, which has a page for each of the 17 goals. We have refreshed it with the latest release, which updated 261 of our charts, covering everything from hunger and schooling to water, work, cities, and oceans.

The International Renewable Energy Agency (IRENA) is an intergovernmental organization with 172 countries and the European Union. Its Renewable Energy Statistics is a reference dataset on how much renewable power capacity has been installed around the world.

IRENA gathers the figures each year from national statistical offices, energy ministries, and industry associations, and fills gaps from official reports. The data covers almost every country from 2000 to 2025, broken down by technology: solar, wind, hydropower, bioenergy, geothermal, and others.

The chart shows the total solar capacity installed in each country, in gigawatts. Note that the figures are cumulative: they count every panel still in operation, not only those added in a given year.

The world added more than 500 gigawatts of solar in 2025 alone — more than twice all the solar capacity that existed anywhere in 2015. China alone accounts for half of the world’s cumulative total, with 1,200 gigawatts.

I recently updated our charts with IRENA’s July 2026 release, which adds data for 2025. In the same pass, I updated two other IRENA datasets we rely on: the cost of electricity from renewable plants, and patents in renewable energy technologies.

The World Bank’s Worldwide Bureaucracy Indicators (WWBI) is a key dataset that helps us understand employment and wages in the public sector: how many people work there; their age, gender, and education; how their pay compares with the private sector; and more.

The World Bank bases these figures on household and labor force surveys and administrative records. The WWBI covers around 200 countries and economies and has data going back to 2000, though coverage varies by indicator.

The map here shows one of the WWBI’s key indicators: public sector employment as a share of total employment. Because that total includes the self-employed, the share is smaller in countries where many people work for themselves, as is the case in much of South Asia and Sub-Saharan Africa.

I recently updated this chart with the latest WWBI release, which adds data for 2021 and 2022 for a handful of countries and earlier years for many more. Because these surveys aren’t run every year, most countries’ latest data is from 2020 or earlier, and the map shows each country’s most recent year since 2012.

The World Development Indicators (WDI) is the World Bank’s compilation of statistics on global development. It covers over 1,500 indicators for more than 200 countries and territories, with some series going back to 1960. It spans topics from economic growth and trade to health, education, energy, infrastructure, and much more.

Most of the data in it is collected by others, including national statistical offices, UN agencies, and researchers.

The World Bank brings these series together in one database and tries to make the data as comparable as possible across countries and over time. That makes it a useful resource for tracking how countries differ from each other and how they have changed over the decades. The WDI is one of the key sources we use at Our World in Data.

I recently updated more than 400 of our charts with the latest release from the World Bank, which updates and extends the WDI in several ways.

For instance, it restructures the World Governance Indicators, a widely cited measure of institutional quality, and adds new Women, Business, and the Law indices, which track legal barriers to women's economic participation across countries.

Researchers and policymakers often need to compare countries by income, which means having clear criteria for who counts as "rich" or "poor".

One widely used approach is the World Bank’s (WB) income classification system, which places countries into four groups — low, lower-middle, upper-middle, and high income — based on their gross national income per capita in the previous year.

These income groups are used across many international datasets, such as the WB’s World Development Indicators — which include information on topics from access to energy and education to global trade — and are often cited in research and the media.

I recently updated our charts with the latest WB classification, published in July this year based on incomes in 2025. You can see this in the map. The WB publishes updates every July, so we'll refresh our charts again in 2027.

Global whale populations fell dramatically over the 20th century due to human hunting. Some whale species were pushed to the brink of extinction.

But a combination of conservation efforts, technological change, economic incentives, and international policies has reduced global whaling to much lower levels. In the mid-1980s, a global moratorium was agreed by the International Whaling Commission (IWC), making commercial whaling illegal.

You can see this decline in the chart, which shows the number of whales killed per decade. The chart combines data from two sources: before the 1990s it comes from the paper “Emptying the Oceans” by Robert C. Rocha, Jr. and colleagues; since then, it comes from the IWC.

While whaling activity is much lower, it hasn’t been eliminated completely. There are exceptions to the IWC’s moratorium, and Japan withdrew from the IWC completely in 2019.

I recently updated our charts with the IWC’s latest annual release, which includes the numbers of whales caught and killed up to 2024.