As reported by this press release from the Bureau of Justice Statistics.
An excerpt.
“Presents data on numbers of jails as well as analyzes patterns of growth and decline in jail populations. These statistical tables include data on rated capacity of jails, percent of capacity occupied, and capacity added. They provide estimates of admissions to jails and detail the volume of movement among the jail population. This web document also includes total numbers for jail inmates by sex, race, and Hispanic origin. Standard errors for jail estimates are included.
“Highlights include the following:
• Between midyear 2009 and midyear 2010, the confined inmate population in county and city jails (748,728) declined by 2.4% (18,706 inmates).
• On June 30, 2010, adults represented 99% of all jail inmates. Males accounted for 87.7%, and females accounted for 12.3%.
• The estimated rated capacity for all jail jurisdictions at midyear 2010 reached 866,974 beds, an increase of 2.0% (17,079 beds) from midyear 2009.”