Last Thursday, Barack Obama became the first sitting US president to visit a federal prison
His visit to the El Reno Correctional Institution was part of a week long focus on reforming the US criminal justice system and possibly reducing the country's huge prison population.
Across the world, there are approximately 10.2 million people in prison with the US accounting for a quarter of them, according to the International Centre for Prison Studies. When it comes to prisoners per 100,000 of the population, the Seychelles comes first with 868 (though it only has 786 prisoners in total). The United States has 2.2 million prisoners - 698 per 100,000 people.
This chart shows prisoners per 100,000 of the population.
You will find more statistics at Statista