[USA] Justice Dept. Numbers Show Prison Trends / New York Times, 6 December 2007
http://www.nytimes.com/2007/12/06/us/06prison.html
SOLOMON MOORE
"About one in every 31 adults in the US was in prison, in jail or on supervised release at the end of last year, the Department of Justice reported. An estimated 2.38 million people were incarcerated in state and federal facilities, an increase of 2.8 percent over 2005, while a record 5 million people were on parole or probation, an increase of 1.8 percent. Immigration detention facilities had the greatest growth rate last year. The number of people held in Immigration and Customs Enforcement detention facilities grew 43 percent, to 14,482 from 10,104."
[USA] Prisoners in 2006 / US. Department of Justice, 5 December 2007
http://www.ojp.gov/bjs/abstract/p06.htm