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Daily Data Insights

Bite-sized insights on how the world is changing, published every weekday.

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Line chart showing cereal yields from 1961 to 2022, measured in tonnes per hectare. Maize, rice, wheat, and barley yields have significantly increased, with maize reaching about 6 t/ha and rice around 5 t/ha by 2022. In contrast, millet and sorghum yields have remained relatively stagnant at around 1 t/ha. Data source: Food and Agriculture Division of the United Nations, via Our World in Data.

Global cereal yields have increased a lot, but millet and sorghum lag behind

Global average yields of cereal crops have tripled over the past 60 years. This has been crucial to feeding a growing population while sparing natural habitat from expanding agricultural land.

However, some cereal crops have seen much larger gains in efficiency. Maize (corn) and rice achieve the highest yields and have seen huge gains in recent decades. Wheat and barley have also performed well.

As the chart shows, crops like sorghum and millet have lagged behind. A hectare of land could yield 5 to 6 tonnes of corn or rice but only 1 to 1.5 tonnes of millet and sorghum.

It’s not just that yields for these crops are much lower today; growth over the past 60 years has been much more modest, increasing by less than 50%.

This is a huge challenge since these are key staple crops across much of Sub-Saharan Africa, where hunger rates are the highest and farmer incomes are the lowest.

Read more in my article on increasing yields in Sub-Saharan Africa →

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A set of four line graphs showing government health expenditure as a percentage of GDP from 1990 to 2021 for Japan, Germany, United Kingdom, and United States. Japan increased from 4.5% to 9.3%, Germany from 6.1% to 11%, the UK from 4.3% to 9.9%, and the US from 4.5% to 16%. Each country is represented by its national flag and name. All graphs show an upward trend, with the US showing the steepest increase, particularly in recent years. The source is cited as Our World In Data based on Lindert (1994), OECD (1993), with a note indicating the metric includes social as well as compulsory health insurance.

Health spending has been rising across rich countries with different systems

Government spending on health has grown substantially across rich nations since 1990, with particularly steep increases in the United States. The chart shows healthcare spending as a share of gross domestic product (GDP) in four countries.

Japan and the UK saw their share more than double, while it more than tripled in the United States, from 4.5% to 16% of GDP. The rising costs partly reflect demographic change, as older populations typically need more medical care, as well as the COVID-19 pandemic.

Each country organizes healthcare differently. Germany requires everyone to buy insurance from regulated providers, while Japan gives everyone government insurance. The United Kingdom provides healthcare directly through its national health service, while the US combines private insurance with government coverage for the elderly and those on low incomes.

Explore government health spending for more countries →

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Line chart showing maternal mortality rates in Sierra Leone from 2000 to 2020. The rate was 1,680 maternal deaths per 100,000 live births in 2000 and declined steadily to 440 per 100,000 by 2020, a 74% reduction. Data source: UN MMEIG (2023).

Sierra Leone has reduced maternal death rates by almost 75% since 2000

In 2000, Sierra Leone had the highest rate of maternal mortality in the world (alongside South Sudan). Around 1,800 pregnant women died for every 100,000 live births.

Since then, risks for mothers have plummeted. The country has focused on expanding healthcare, increasing the retention of skilled medical staff, and improving access to crucial medicines and treatments. In 2010, it rolled out free healthcare to pregnant women and children.

The results are shown in the chart. Maternal mortality rates have fallen by 74% in two decades.

While these rates are still extremely high — rates in the safest countries are around 100 times lower — Sierra Leone has made massive strides in saving both women and children.

Explore more global data on maternal deaths and declines over time →

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A bar chart displays the percentage of national income that various developed countries allocated as Official Development Assistance (ODA) to the least developed nations in 2022, compared to a target of at least 0.15%. The bar for Luxembourg shows the highest percentage at 0.46%, followed by Sweden at 0.28% and Norway at 0.2%. Other countries listed include Iceland and Denmark at 0.14%, Belgium at 0.13%, Switzerland, Netherlands, and Japan all at 0.12%, each followed by Germany, France, and Ireland at 0.11%. Canada provides 0.1%, while the United States and the United Kingdom each contribute 0.08%. Austria gives 0.07%, Slovenia and South Korea both provide 0.06%, and Italy is at the lowest at 0.05%. 

Data source: OECD (2024). The note indicates that it represents the 20 OECD nations providing the most aid, percentage-wise, to the poorest nations.

Most OECD countries fail to reach the UN’s target for aid to the poorest countries

In 1981, the major foreign aid donor countries, also known as the Development Assistance Committee, made a promise at the UN: to aim for at least 0.15% of their national income to assist the world's least developed countries — about 1 dollar out of 700.

Over the years, they repeated this pledge. But by 2022, most countries failed to honor this promise. The chart shows the 20 OECD countries giving the most aid, as a percentage of their national income, to the world’s poorest nations.

Only three countries met the target: Luxembourg, Sweden, and Norway.

Some countries are so wealthy that even a rounding error in their budgets could mean the difference between life and death for people in the poorest parts of the world.

Explore foreign aid given to least-developed countries for all donor countries →

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A bar graph compares cancer survival rates after five years for patients diagnosed in 2014 in Australia and the U.K. The title states that cancer survival rates are higher in Australia. 

For colorectal cancer, 71% of Australian patients are alive after five years compared to 60% in the U.K. In ovarian cancer, the survival rates are 44% in Australia and 37% in the U.K. Stomach cancer shows a survival rate of 33% in Australia versus 21% in the U.K. 

Liver cancer survival is at 21% in Australia, while 13% are alive in the U.K. Lung cancer survival rates are 21% in Australia and 15% in the U.K. Finally, for pancreatic cancer, 14% of Australian patients survive five years post-diagnosis compared to 8% in the U.K. 

Data source is listed as Global Cancer Observatory from 2019.

Patients in the United Kingdom are less likely to survive cancer five years after diagnosis than in Australia

Patients diagnosed with cancer in 2014 were more likely to survive in Australia than in the UK across multiple types of cancer. This is despite both countries having similar socio-economic conditions, allocating a comparable amount per person to healthcare, and having a similar share of their populations living with cancer.

For colorectal cancer, 71% of Australian patients survived five years after diagnosis, compared to 60% in the UK.

Lung, liver, and pancreatic cancers, which are among the most aggressive, also had lower survival rates in the UK.

The survival gap was most dramatic for pancreatic cancer patients, where Australia's 14% five-year survival rate was nearly double the UK's 8%.

These survival rates only account for diagnosed patients, meaning early detection and prompt treatment access significantly impact outcomes. Differences in healthcare systems, screening coverage, treatment approaches, and other health risk factors may contribute to the gap.

Explore how cancer survival rates compare across other countries →

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A line chart titled "The number of children in South Korea has fallen rapidly since the 1970s." It shows the number of young people under age 15 peaking at 14 million in the 1970s and declining steadily to 5.7 million by 2023, a decrease of 60%. The x-axis represents years from 1950 to 2023, while the y-axis represents the population in millions. Data source: UN, World Population Prospects (2024).

The number of children in South Korea has fallen by 60% since its peak

South Korea is undergoing one of the world’s most rapid demographic transitions. Fertility rates — the number of children a woman has over her lifetime — have fallen rapidly over the last 50 years, and this is reflected in a rapidly aging population.

One of the clearest signs is the total number of children living in South Korea. In the chart, you can see that the number of children and adolescents under 15 years old is shrinking quickly.

The number of under-15s peaked around a decade later but has now fallen by 60%, from 14 million to less than 6 million.

This is a pattern we see in other countries such as Japan, China, and even Thailand — albeit at different rates.

Explore more data on population trends, births, and fertility rates in our Population and Demography data explorer →

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Bar chart titled "The US spends far more on health than any other G7 country." It compares public and private annual health expenditures per person (2021) among G7 countries, adjusted for living cost differences. The US leads significantly at $12,000, followed by Germany at $7,610, Canada at $6,550, France at $6,330, the UK at $6,160, Japan at $4,680, and Italy at $4,370. Data source: World Health Organization (2025), using international-$ at 2017 prices.

The United States spends a lot more on healthcare per person than other G7 nations

The chart shows health expenditure per person for G7 countries; the data is adjusted for differences in living costs between countries.

The US spends much more on healthcare per person than any other G7 nation: $12,000 in 2021. This is more than 50% higher than Germany, the next-highest spender.

Japan and Italy spend just $4,700 and $4,400 per person at the lowest end — slightly over one-third of US spending.

Despite spending much more on healthcare, the United States has the lowest life expectancy in the G7. This is due to a combination of higher death rates from smoking, obesity, homicides, opioid overdoses, road accidents, and infant mortality.

Explore health expenditure per person for other countries →

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What share of children die before their fifth birthday?

What could be more tragic than the death of a young child? Child mortality, the death of children under the age of five, is still extremely common in our world today.

The historical data makes clear that it doesn’t have to be this way: it is possible for societies to protect their children and reduce child mortality to very low rates. For child mortality to reach low levels, many things have to go right at the same time: good healthcare, good nutrition, clean water and sanitation, maternal health, and high living standards. We can, therefore, think of child mortality as a proxy indicator of a country’s living conditions.

The chart shows our long-run data on child mortality, which allows you to see how child mortality has changed in countries around the world.

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Share of population living in extreme povertyWorld Bank

Life expectancy at birthLong-run estimates collated from multiple sources by Our World in Data

Per capita COâ‚‚ emissionsLong-run estimates from the Global Carbon Budget

GDP per capitaLong-run estimates from the Maddison Project Database

Share of people that are undernourishedFAO

Literacy rateLong-run estimates collated from multiple sources by Our World in Data

Share of the population with access to electricityWorld Bank

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