Allen J. Beck of the U.S. Justice Department's Bureau of Justice Statistics and colleagues found about 7.5 percent alleged they were victimized while in a state prison, 1.8 percent while in a local jail and 0.1 percent while in a post-release community treatment facility.
An estimated 3.7 percent of former prisoners said they were forced or pressured to have non-consensual sex with another inmate while 5.3 percent reported an incident that involved facility staff, the report said. Incidents of non-consensual sex included manual stimulation and oral, anal or vaginal penetration.
The findings are based on the National Former Prisoners Survey, part of Bureau of Justice Statistics' National Prison Rape Statistics Program, which has collected corrections administrative records of reported sexual violence or allegations of sexual victimization directly from victims since 2004.
The report said the rate of inmate-on-inmate sexual victimization among former state prisoners was at least three times higher for females, 13.7 percent, than males, 4.2 percent.
Thirty-nine percent of gay male former prisoners and 34 percent of bisexual male former prisoners reported sexual victimization by other inmates, compared to 3.5 percent of heterosexual males, the report said.