Earlier this week, the Bill and Melinda Gates Foundation published their annual letter that highlights the surprises they saw in 2018, as well as the philanthropic opportunities they’ve identified for the future.

Among many other compelling facts and stories, the letter pointed out one surprise that we thought was of particular interest: the median age of the African continent is just 18 years old.

Image: Visual Capitalist

Median ages, by continent

Today’s chart was inspired by the Gates’ letter, and it showcases the median age of each continent along with other pertinent data points.

What’s interesting here is not only Africa’s median age, but also that the median age for each other continent is at least 13 years older. In other words, this means Africa is a real demographic outlier.

In their letter, Bill and Melinda Gates drop one additional fact that helps crystallize this even further: by 2100, it’s projected that nearly half of the world’s children aged 0-4 years old will be in Sub-Saharan Africa.

Median ages, by country

The difference in median age between Africa and Europe is quite astonishing, but the gap gets even wider when we look at individual countries.

For example, Monaco is the country with the oldest population in the world with a median age of 53.1 years – but this is roughly 3.5x higher than the median age of Niger, where it is just 15.4 years.

Here are the five oldest countries, along with the five youngest:

While it is not surprising that Monaco – a small and wealthy city-state that sits on the French Riviera with a population of just 40,000 people – is the oldest country in the world, it seems that age could be a real challenge for the major economies that also make this list.

Germany, Italy, and Japan have some of the largest economies in the world with a combined nominal GDP equal to 12.2% of global output. At the same time, they are also three of the oldest countries right now, and they are each projected to hit a median age of 50 years or higher by the year 2050.

On the other end of the spectrum, there are more than 30 countries that have median ages under 20 years, with most of them existing in Africa or the Middle East. One exception to this is Timor-Leste, a small country bordering Indonesia, which has a median age of 18.9 years.