The second edition (2000) of the World Prison Population List shows that over 8 ½ million people are held in penal institutions throughout the world, either as pre-trial detainees (remand prisoners) or having been convicted and sentenced. Half of these are in the United States, Russia and China, and the first two countries also exhibit the highest prison population rates.
At the beginning of the year 2000, Russia had the highest prison population rate in the world, some 730 per 100,000 of the national population, followed by the USA (690). After these two countries come Belarus and Kazakhstan, and four small territories in the central America/Caribbean region whose high rates owe much to the imprisonment of drug smugglers who are not nationals of the countries in question - Belize, the Bahamas, the Cayman Islands and the US Virgin Islands. All these countries have rates of at least 460 per 100,000. It needs to be emphasised that their rates of between 460 and 730 per 100,000 are vastly greater than what is to be found in most parts of the world, since two thirds of countries have rates of 150 per 100,000 or below.
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The number of people imprisoned in the United States is at record levels and will exceed two million by the end of this year, authorities say.
Source.
More:
http://www.aic.gov.au/stats/international/wpl.html
http://www.aic.gov.au/stats/international/
So, almost a quarter of the world's prison population in the USA. Why?