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Our World in Data @OurWorldInData

Our World in Data is a free, nonprofit website with a mission to increase understanding of the world’s largest problems and drive informed action to solve them.

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Our World in Data
@OurWorldInData
Jan 3
All three statements are true at the same time—
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Just over one-third of the world’s assessed fish stocks are overexploited— How much of the world’s fish stocks are overfished? Fisheries scientists often answer this question with a specific metric: the “maximum sustainable yield” — this is the largest catch that can be taken from a fish stock without depleting it to the point that future catches decline. When a stock is fished at a rate above this level, it is considered overfished. The Food and Agriculture Organization of the United Nations (UN FAO) estimates that just over one-third of the world’s assessed fish stocks are overfished. As the chart shows, this has increased from around 10% in the mid-1970s. Getting high-quality global estimates of this metric is difficult; many regions have formal assessments of fish stocks and catch rates, but many fish stocks across Africa, Asia, and South America are not assessed rigorously. To get global estimates, the UN FAO combines these formal assessments with expert opinion and extrapolations based on available national and regional data. The FAO’s report — The State of World Fisheries and Aquaculture 2024 — provides more detailed breakdowns of which species are overfished. (This Data Insight was written by @_HannahRitchie and @parriagadap.)
Stacked area chart of the share of assessed global fish stocks classified as biologically sustainable versus overexploited from 1974 to 2021, where the overexploited share rises from the 1970s and is about 35% in 2021 while biologically sustainable is about 65%. Data source: Food and Agriculture Organization of the United Nations (2025). License: CC BY.

ALT Stacked area chart of the share of assessed global fish stocks classified as biologically sustainable versus overexploited from 1974 to 2021, where the overexploited share rises from the 1970s and is about 35% in 2021 while biologically sustainable is about 65%. Data source: Food and Agriculture Organization of the United Nations (2025). License: CC BY.

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Explore more data and research on overfishing: ourworldindata.org/fish-and-…

Fish and Overfishing

How are fish stocks changing across the world? How much is overfished?

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How can we measure the state of democracy around the world? Measuring democracy is challenging. It has many dimensions, and researchers assess them in different ways. No single source of data captures the full picture, so we present data from several of them. These include Varieties of Democracy (V-Dem; shown in the map here), the Lexical Index, Freedom House, and the Bertelsmann Transformation Index. Some of these data sources focus on broad characteristics of political systems to identify which countries are democracies at all. Others use expert surveys to assess smaller differences in the degree of democracy. Our colleagues Mojmír Vinkler and @lucasrodesg recently updated more than 250 of our democracy charts with the latest available data from our sources, which now include data for 2025.
Choropleth map of country-level Liberal Democracy Index for 2025 where it highlights global differences in democratic scores on a scale from 0 to 1. High scores are concentrated in North America, Western and Northern Europe, Australia and New Zealand, while lower scores appear across parts of Africa, the Middle East, and Central and East Asia; many countries in Latin America and southern Africa show intermediate values. A few areas are marked as having no data. The data source is the Varieties of Democracy (V-Dem) project (2026). The chart is licensed CC BY to Our World in Data.

ALT Choropleth map of country-level Liberal Democracy Index for 2025 where it highlights global differences in democratic scores on a scale from 0 to 1. High scores are concentrated in North America, Western and Northern Europe, Australia and New Zealand, while lower scores appear across parts of Africa, the Middle East, and Central and East Asia; many countries in Latin America and southern Africa show intermediate values. A few areas are marked as having no data. The data source is the Varieties of Democracy (V-Dem) project (2026). The chart is licensed CC BY to Our World in Data.

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Explore all of the updated data in our interactive charts: ourworldindata.org/search?da…

Search

Search articles and charts on Our World in Data. Filter by country or subject area to discover insights on global issues supported by reliable data.

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Our colleague @bbherre wrote a full article explaining how these data sources differ and when to use which one: ourworldindata.org/democraci…

Democracy data: how sources differ and when to use which one

There are many ways to classify and measure political systems. What approaches do different sources take? And when is which approach best?

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Spain and Portugal both get over 40% of their electricity from solar and wind— On the Iberian Peninsula, Spain and Portugal have scaled up solar and wind power almost in step. In the chart, you can see the share of electricity coming from solar and wind. Both countries generated over 40% of their electricity from these sources in 2025. That was higher than the European Union average of 30%. The two countries have very similar geographies and share an electricity market. They also have weak connections to the rest of the European electricity grid, forcing them to generate clean power at home rather than rely on imports. Wind power is more prevalent in Portugal, while solar is ahead in Spain. (This Data Insight was written by @_HannahRitchie and @parriagadap.)
Line chart of the share of electricity generated from solar and wind in Spain and Portugal from 1985 to 2025 where both countries rise from near zero to over 40% by 2025, with Portugal at 44% and Spain at 42% in 2025. Data source: Ember (2026). License: CC BY to Our World in Data.

ALT Line chart of the share of electricity generated from solar and wind in Spain and Portugal from 1985 to 2025 where both countries rise from near zero to over 40% by 2025, with Portugal at 44% and Spain at 42% in 2025. Data source: Ember (2026). License: CC BY to Our World in Data.

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Explore more data on the rollout of clean energy across the world: ourworldindata.org/explorers…

Energy Data Explorer

Explore data on energy production and sources.

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The cost of computer memory and storage has fallen exponentially.
Line chart showing the historical price of computer memory and storage from 1956 to 2023. Expressed in US dollars per terabyte (TB), adjusted for inflation. Shown: "Memory" refers to random access memory (RAM), "disk" to magnetic storage, "flash" to special memory used for rapid data access and rewriting, and "solid state" to solid-state drives (SSDs). Data source: McCallum (2023); U.S. Bureau of Labor Statistics (2026). Chart is licensed CC BY.

ALT Line chart showing the historical price of computer memory and storage from 1956 to 2023. Expressed in US dollars per terabyte (TB), adjusted for inflation. Shown: "Memory" refers to random access memory (RAM), "disk" to magnetic storage, "flash" to special memory used for rapid data access and rewriting, and "solid state" to solid-state drives (SSDs). Data source: McCallum (2023); U.S. Bureau of Labor Statistics (2026). Chart is licensed CC BY.

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Exponential growth is at the heart of the rapid increase of computing capabilities in the last decades. Learn more in our articles: "What is Moore's Law?": ourworldindata.org/moores-la…

What is Moore's Law?

Exponential growth is at the heart of the rapid increase of computing capabilities.

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“Scaling up: how increasing inputs has made artificial intelligence more capable”: ourworldindata.org/scaling-u…

Scaling up: how increasing inputs has made artificial intelligence more capable

The path to recent advanced AI systems has been more about building larger systems than making scientific breakthroughs.

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How much do countries spend on their militaries? How has this changed over time, and how do different countries compare? The Stockholm International Peace Research Institute (@SIPRIorg) provides a key resource for answering these questions and more. SIPRI compiles the most consistent long-run data available on military spending: in absolute terms (as shown in the chart here) and as a share of both GDP and overall government spending. SIPRI builds the database from open sources — defense budgets, audit reports, and IMF and World Bank figures — and adjusts for differences in how countries report their fiscal years, so the numbers are comparable across borders. The latest release covers around 150 countries from 1949 to 2025, though not all countries and regions have data for the full period. Our colleague @parriagadap recently updated our charts with the latest release. SIPRI updates this data annually, with the next release expected around April 2027.
Small multiples line charts of military spending by country where they compare annual spending from 1949 to about 2026 in constant 2024 US dollars to show long-term trends. Source: Stockholm International Peace Research Institute (2026). License: CC BY to Our World in Data.

ALT Small multiples line charts of military spending by country where they compare annual spending from 1949 to about 2026 in constant 2024 US dollars to show long-term trends. Source: Stockholm International Peace Research Institute (2026). License: CC BY to Our World in Data.

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Explore the data for all countries in the interactive version of this chart: ourworldindata.org/grapher/m…

Military spending

Includes military and civil personnel, operation and maintenance, procurement, military research and development, infrastructure, and aid. This data is expressed in US dollars and adjusted for...

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Where are more people dying than being born? For most of human history, more people were born each year than died. Populations grew very slowly for most of this history, then rapidly in recent centuries, as child mortality plummeted and people lived longer. But this is changing. As the map shows, deaths now outnumber births in a growing number of countries across Europe and East Asia. The balance of births and deaths tells us about a country’s “natural population change” — whether it would grow or shrink without any international migration. Where deaths outnumber births, the population will shrink unless enough people move in from abroad to make up the gap. (This Data Insight was written by @_HannahRitchie.)
Choropleth world map of natural population growth showing where deaths now outnumber births in 2023, indicating countries that would have a shrinking population without immigration; it shows much of Europe, Central Asia and East Asia with more deaths than births while most of Africa, South Asia and the Americas have more births than deaths. Data source: UN World Population Prospects (2024), data for 2023. License: CC BY.

ALT Choropleth world map of natural population growth showing where deaths now outnumber births in 2023, indicating countries that would have a shrinking population without immigration; it shows much of Europe, Central Asia and East Asia with more deaths than births while most of Africa, South Asia and the Americas have more births than deaths. Data source: UN World Population Prospects (2024), data for 2023. License: CC BY.

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Explore how the number of deaths and births is changing in your own country: ourworldindata.org/grapher/b…

Births and deaths per year

Future projections are based on the UN's medium scenario.

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The world has become much more resilient to disaster events over the last century. In the chart here, you can see estimates of average death rates — measured as the number of deaths per 100,000 people — by decade since the early 20th century. Over the last century, death rates have fallen by more than 90%. Records from a century ago are much less complete, with many small and medium-sized events missed, so this may even be an underestimate. This is not because hazards have become weaker. It’s because societies have become more resilient. – Weather forecasting has allowed us to know when disasters are coming ahead of time, giving societies time to prepare. – Early warning systems allow local populations to take cover and stay safe. – Better buildings can withstand earthquakes and hurricanes. – National and international cooperation, combined with transport and trade, means others can provide assistance when a disaster does strike. – Food systems are more productive and better connected, making the impact of a lost harvest less severe than it would have been a century ago. Continuing to improve the resilience of systems worldwide remains crucial to reducing the toll from disasters in the future.
Stacked bar chart of global annual death rates from natural disasters (decadal averages of deaths per 100,000 people) where the 1920s and 1940s show major peaks largely driven by droughts and floods and rates are much lower from about 1960 onward. Data source: EM-DAT, CRED / UCLouvain (2026); population data based on various sources (2024). License: CC BY. Coverage is more limited before the year 2000, so longer historical trends may partly reflect reporting improvements.

ALT Stacked bar chart of global annual death rates from natural disasters (decadal averages of deaths per 100,000 people) where the 1920s and 1940s show major peaks largely driven by droughts and floods and rates are much lower from about 1960 onward. Data source: EM-DAT, CRED / UCLouvain (2026); population data based on various sources (2024). License: CC BY. Coverage is more limited before the year 2000, so longer historical trends may partly reflect reporting improvements.

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Explore all of our data and research on disasters on our new page, published today: ourworldindata.org/natural-d…

Natural Disasters

How many people die from disasters, and how are the impacts of disasters changing over time?

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What is the largest source of electricity in each country? Coal generates one-third of the world’s electricity, more than any other source. But zoom into the country level, and the picture is much more varied. The map shows which source generated the most power in each country in 2024 or 2025 (the latest year available). Thanks to large reserves, coal dominates across Asia. It’s the largest source in China, India, Indonesia, and Malaysia. These are huge power producers, which is why coal is so dominant at a global level. Across most other regions, it’s mostly a mix of gas and hydropower. On islands and parts of North Africa, it’s oil. Europe has the most diverse mix, with nuclear power dominating generation in countries such as France and Finland, and solar and wind overtaking fossil fuels as the largest sources in countries such as Spain and Germany. Solar and wind are growing quickly in many countries; when these sources are combined as “variable renewables”, they become the largest source in six more countries: the Netherlands, Portugal, Greece, the United Kingdom, Belgium, and Pakistan. (This Data Insight was written by @_HannahRitchie.)
World map of the largest source of electricity in 2024/25 by country, with country labels showing the share of generation coming from that largest source. The map shows many countries dominated by coal, gas, or hydropower, with notable examples labeled such as Norway at 90% hydropower, France about 69% nuclear, Chile about one-quarter solar, and Australia 43% coal. Data source: Ember (2026). License: CC BY.

ALT World map of the largest source of electricity in 2024/25 by country, with country labels showing the share of generation coming from that largest source. The map shows many countries dominated by coal, gas, or hydropower, with notable examples labeled such as Norway at 90% hydropower, France about 69% nuclear, Chile about one-quarter solar, and Australia 43% coal. Data source: Ember (2026). License: CC BY.

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Explore the electricity mix across the world, and see how it’s changing over time: ourworldindata.org/grapher/s…

Share of electricity production by source

An interactive visualization from Our World in Data.

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Our World in Data retweeted
Daniel Bachler
@DanyX23
Jun 5
Replying to @tom_sasse @Noahpinion
At @OurWorldInData we recently built a tool that allows anyone to create their own projections - it might be of interest to readers who want to explore more scenarios: ourworldindata.org/populatio…

Population tool: How will populations across the world change in the 21st century?

We created an interactive tool that lets you test how changes in fertility rates, life expectancy, and migration rates will change future populations.

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