"During 2010, the number of persons under supervision of adult correctional authorities declined by 1.3% (91,700 offenders), reaching 7.1 million at yearend. This was the second consecutive year of decline in the correctional population. The population at yearend 2010 dropped below the 2006 level (7.2 million). The adult correctional systems supervise offenders in the community under the authority of adult probation or parole agencies and those incarcerated in state or federal prisons or local jails. (See text box below.) This report provides summary data on the total population under the supervision of the adult correctional systems and highlights significant changes in the components of the population."
Bureau of Justice Statistics: http://bjs.ojp.usdoj.gov/