The US prison population ballooned eight-fold between 1970 and 2005 and will grow by an additional 192,000 convicts by 2011, according to a new study.
The report by the Pew Charitable Trusts said one in 178 US residents will live in prison by 2011 and the increase could cost American taxpayers another 27.5 billion dollars over the next five years in jail spending.
"After a 700-percent increase in the US prison population between 1970 and 2005, you'd think the nation would finally have run out of lawbreakers to put behind bars," said the report by Pew's Public Safety Performance Project.
But figures provided by US states show that 1.7 million people will be behind bars in 2011, a 13 percent increase that is three times the growth rate of the US population, the study said.
The Pew data does not include local prisons, whose population in 2005 was nearly 750,000, bringing the total US prison population to 2.2 million people, the largest in the world.
The jail growth will cost states another 15 billion dollars for prison operations and an additional 12.5 billion dollars to build new prisons.