Sorry I stand corrected about the incarceration totals, although the United States does have the highest rates of imprisonment in the world, the actual totals are even greater than China which has over 5 times the population. The US total is not greater than the rest of the world combined although it accounts for a very large percentile of the total.

http://www.homeoffice.gov.uk/rds/pdfs2/r188.pdf

The total imprisoned throughout the world stands at 8.75 million imprisoned. The US accounts for over 2 million of that total figure. Roughly 1 in every 4 people imprisoned throughout the world is an American Citizen.

As the data is some 4-5 years old, the total percentage which would be US incarcerations compared to the overall world total has become even higher.