Out of 223 countries, the United States imprisons the largest number of people, with 2,217,000 inmates as of 2015, compared to San Marino, with a mere two inmates. Liechtenstein houses the largest percentage of female inmates, with 22.2 percent of prisoners identifying as female, whereas there are no women imprisoned in New Zealand, Micronesia, Tuvalu, San Marino and the Marshall Islands.
In the United States, there were a disproportionate amount of black and African American people incarcerated in 2011, with approximately half a million male and 26,000 female inmates in this demographic. As this group comprised 40 percent of all prisoners in the United States, they only made up 13 percent of the U.S. population. The same year, nearly 237,000 prisoners were convicted of drug-related offenses, including possession and trafficking, making it the most common conviction of inmates. Murder and robbery closely followed.
China housed roughly 1.7 million prisoners in 2014, making it the only country that incarcerated anywhere close to the number of people that the United States incarcerated. With approximately 18 million people incarcerated worldwide, nearly half of them are in the United States, Russia and China.
Although developing countries have lower rates of incarceration, many of them suffer substantial overcrowding. For example, prisons in Kenya have an occupancy rate of 343.7 percent.