From today's New York Times:
Nationwide, the prison population grew by 25,000 last year, bringing it to almost 1.6 million. Another 723,000 people are in local jails. The number of American adults is about 230 million, meaning that one in every 99.1 adults is behind bars.
Incarceration rates are even higher for some groups. One in 36 Hispanic adults is behind bars, based on Justice Department figures for 2006. One in 15 black adults is, too, as is one in nine black men between the ages of 20 and 34.
This is, of course, quite natural! According to a Professor Paul Cassell, from the University of Utah, who gets quoted later on in the article,
"One out of every 100 adults is behind bars because one out of every 100 adults has committed a serious criminal offense."