June 13, 2024
One of the most transformative changes in technology over the last few decades has been the massive drop in the cost of clean energy. Solar photovoltaic costs have fallen by 90% in the last decade, onshore wind by 70%, and batteries by more than 90%.
These technologies have followed a “learning curve” called Wright’s Law. This states that the cost of technology falls consistently as the cumulative production of that technology increases.
The chart shows the perfect example of this for solar power. This data comes from the International Renewable Agency, Greg Nemet, and Doyne Farmer & François Lafond.
On the horizontal axis, we have the cumulative installed capacity of solar panels, and on the vertical axis, the cost. Both are measured on logarithmic scales, and the trend follows a straight line. That means the fall in cost has been exponential.
Costs have fallen by around 20% every time the global cumulative capacity doubles. Over four decades, solar power has transformed from one of the most expensive electricity sources to the cheapest in many countries.
Technologies that follow Wright’s Law get cheaper at a consistent rate, as the cumulative production of that technology increases.
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Today
On average, Americans spend about the same amount on food consumed at home as they did in the 1950s. But they spend a lot more in restaurants, cafes, and at work.
The chart shows the average amount of money spent on food, at home and away from home in the United States. This is based on data from the USDA Economic Research Service. It’s adjusted for inflation over time.
Today, the amount spent on food away from home is about the same as what is spent on food at home.
Explore data on food expenditure across the world →
October 11
Teenage pregnancy rates have fallen across all regions in the last few decades.
The chart shows the number of live births per 1,000 women aged 15 to 19 since 2000, based on data compiled by the United Nations.
Globally, rates have fallen by around one-third. This decline has been even more dramatic in some regions. For example, rates have fallen by more than two-thirds in Central and South Asia.
Birth rates have also fallen among adolescents aged 10 to 14 years old, where health concerns for pregnancy in such young girls are even greater.
Explore teenage pregnancy data for individual countries over time →
October 10
When it comes to demographic trends, few are as well known as the “baby boom”.
The baby boom was a sharp rise in the fertility rate toward the end of the Second World War and for decades after. It happened in several countries around the world, but it was especially pronounced in the United States.
Before the baby boom, the US had seen a long-term decline in the fertility rate, down to about 2 children per woman by the 1930s.
During the baby boom, the fertility rate rose sharply, almost doubling to nearly 4 children per woman — levels that hadn’t been seen since the beginning of the 20th century. By the early 1970s, the fertility rate had returned to about 2 children per woman. Today, it’s just over 1.6.
It’s estimated that more than 70 million people were born in the US between 1946 and 1964, the official years of the baby boom according to the US Census Bureau. By 1964, this generation comprised almost 40% of the nation’s population.
As such a large generation, “baby boomers” have played a significant role in shaping many social, economic, and political trends in modern US history.
Learn more about fertility rates over time →
October 09
The number of people dying in road accidents in the United Kingdom has fallen by around three-quarters since 1970.
The chart shows the number of road deaths over time, based on data from the OECD, which we just updated. This includes the deaths of pedestrians, drivers, passengers, and cyclists.
In the early 1970s, there were around 8,000 road deaths per year. This has dropped below 2,000 in recent years. Deaths reached a low in 2020 due to reduced traffic from the COVID-19 pandemic but have rebounded slightly since then.
This multi-decade decline is even steeper when we look at the number of deaths per kilometer driven.
Explore road death data for other countries →
October 08
In 2023, wind power generated nearly 60% of Denmark’s electricity. This made Denmark the country with the highest share of wind in its electricity mix. This is based on data from Ember.
Wind also contributes significantly to Denmark’s broader energy system. Data from the Energy Institute shows that wind power accounts for over a quarter of Denmark’s total primary energy consumption — the largest figure globally.
Denmark also ranks first in per capita wind power generation, with Sweden close behind.
Explore more data on energy sources in our Data Explorer →
October 07
When I was born in 1993, one-third of people in the United Kingdom said they “would not want homosexual neighbors”. Today, that’s less than 5%.
As you can see in the chart, the acceptance of same-sex relationships has increased in many other countries, too. This data comes from the Integrated Values Survey.
Attitudes to homosexuality tend to be far more positive in Western Europe and North and South America than in other parts of the world. In many countries across Eastern Europe, Asia, and Africa, the majority of surveyed respondents still say they would not want homosexual neighbors.
Explore the data on attitudes to homosexuality across the world →
October 04
Russia’s 2022 invasion of Ukraine has led to increased military spending not only in the two countries themselves but also in other neighboring countries.
The chart, using inflation-adjusted data from the Stockholm International Peace Research Institute, shows that Russia has increased its military spending to support the invasion, while Ukraine has expanded its budget tenfold to defend itself.
The war has also motivated several of Russia’s other neighbors to increase their military spending. For instance, in 2023, Poland almost doubled its military spending from 15 to 27 billion US$, and Finland raised its budget from 4.5 to 6.9 billion US$.
Other neighboring countries, like Lithuania and Estonia, have so far not made increases as dramatic but have returned to the longer-term expansion of their military budgets.
Some Western European countries, especially Denmark, have also already increased their military spending after Russia’s invasion.
Explore military spending data for every country →
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