At current rates, it will take 133 years for America’s population to double given aging demographics and low fertility rates.

By contrast, several countries in Africa and the Middle East are set to double in a quarter century. For instance, Kinshasa, in the DRC, is forecast to be among the most populous cities worldwide by 2080 given rapid population growth.

This graphic, via Visual Capitalist's Dorothy Neufeld, shows the fastest-growing populations in the world, based on data from the United Nations.

Below, we show countries with the fastest annual doubling rates at current projections:

As we can see, Oman and Syria are set to double their population in just 20 years.

Overall, the population of Arab states are projected to double in 36 years, supported by average fertility rates of 3.2 births per women. Yemen and Afghanistan each are set to double in size in 24 and 26 years, respectively.

In Africa, the Central African Republic and Somalia are set to reach this milestone in 21 years, making them the fastest-growing populations on the continent. Perhaps even more strikingly, the DRC, with a population of 112.8 million in 2025, could double by 2047.

Going further, the DRC is set to become the fifth-most populous country in 2100, up from 15th in 2025. Meanwhile, Nigeria is set to the fourth-largest by population after India, China, and Pakistan.

To learn more about this topic, check out this graphic on the fastest shrinking countries in the world.