The United States has the highest incarceration rate in the world. There were 743 prisoners per 100,000 U.S. citizens in 2011, according to the World population list. This is compared to second place Rwanda (595) where many prisoners are being held on counts of genocide, and third place Russia (568). In Australia, the number is 133, and Canada has 114. The average rate for the group of seven excluding the U.S. (Japan, Germany, UK, France, Italy and Canada) is 96. In raw numbers, the U.S. is also number one with 2.2 million people incarcerated.
Even for the U.S., this number is historic. The percentage of the U.S. population in prison has been rising since the 1980s. In 1980, there were about 220 people in jail or prison per 100,000 people in the U.S. That number has almost tripled since then, growing much faster than the total population. The state of New York imprisons almost four times as many people as the entire country of Australia (92,769 vs. 25,353) even though the two have similar total populations.
Housing such a large prison population is expensive. In 2008, the U.S. spent almost $75 billion on corrections through federal, state and local levels. This is more than triple to cost in 1982. The heaviest burden falls on the states, which house 60% of the inmate population. According to the Georgia Department of Corrections, constructing a minimum security prison costs $28,936 per bed. For medium security it is $61,341 per bed, for close security it is $80,046 and for maximum security it is $110,512. The average operational cost of all state prisons in Georgia is $16,502 per inmate per year. Additionally, 61.8% of all U.S. inmates are non-violent offenders, and 24.4% of inmates are non-violent drug offenders. Mandatory minimum sentences and tougher drug laws have made large contributions to the ballooning inmate population.
This system is not without its benefits. Crime has fallen since a 1992 high, indicating that tougher punishments have acted as deterrents and also have removed many criminals from circulation. High rates of imprisonment per crime committed (around 30% in 2000) have had a large impact on crime in the U.S. Comparatively, in the UK and New Zealand shrinking imprisonments per crime have correlated with higher crime rates between 1960 and 2000. There does seem to be diminishing returns on the investment, however. A 10% increase in incarceration leads to about a 2-4% drop in crime, according to Don Stemen, of the Vera Institute of Justice. Since 2000, crime has decreased less rapidly, while incarceration continues to grow steadily, indicating some sort of crime rate plateau.
NCCD 2006 Fact Sheet: http://www.caught.net/incarcerationRate.PDF
The New York Times U.S. Prison Population Dwarfs that of Other Nations: http://www.nytimes.com/2008/04/23/world/americas/23iht-23prison.12253738.html?pagewanted=all
The High Budgetary Cost of Incarceration: http://www.cepr.net/documents/publications/incarceration-2010-06.pdf
Georgia State Board of Pardons and Paroles: http://www.pap.state.ga.us/opencms/export/sites/default/index.html?page=index.html