wikipedia:
In absolute terms, the United States currently has the largest inmate population in the world, with more than 2½ million[10] or more than one in a hundred adults[11] in prison and jails. Although the United States represents less than 5% of the world's population, over 25% of the people incarcerated around the world are housed in the American prison system. Pulitzer Prize winning author Joseph T. Hallinan wrote in his book Going Up the River: Travels in a Prison Nation, "so common is the prison experience that the federal government predicts one in eleven men will be incarcerated in his lifetime, one in four if he is black." In 2002, both Russia and China also had prison populations in excess of 1 million.[12] By October 2006, the Russian prison population declined to 869,814 which translated into 611 prisoners per 100,000 population.
As a percentage of total population, the United States also has the largest imprisoned population, with 739 people per 100,000 serving time, awaiting trial or otherwise detained.[13]
The high proportion of prisoners in some developed countries is from various causes, but the attitude toward drug-taking plays a considerable part. In undeveloped countries, rates of incarceration are often lower, though this is not a rule. In general, such societies have less goods to steal and a more community based social system, with less judicial law-enforcement. Also their economies may not support the high cost of incarceration.