There are quite a lot of prisons in the USA and all of them are quite large. The USA has the highest percentage of prisoners due to its population than any other nation. In 2001, almost 6.6 million people either served sentence or were prescribed a probation term. This number makes 3.1% of all the US grown-up population, i.e. one prisoner per 32 American citizens.
The statistics also shows that since 2001, almost 70 % of all the freed prisoners will be repeatedly arrested within 3 years. It also showed that only 42% of the prisoners served their terms without disciplinary violations.
Today many American prisoners do not get any aid from the government after their return to normal life. Former prisoners can not be employed while enduring the society’s troubles. Due to the statistics, 65% of employers do not wittingly hire a former prisoner in 5 large cities of the US.

Interesting facts:

Average age of a prisoner in the USA is 38
27% of prisoners are not the US citizens
Average sentence term is from 5 to 10 years
In 2006, 60 convicts were executed in 16 states - 59 men and 1 woman.
41 persons were blondes and 19 - dark-skinned.

Source: http://izkolonii.ru