"Correctional authorities supervised 7,225,800 offenders at year end 2009, which was slightly fewer offenders (down 48,800) than in 2008. Correctional supervision includes adults supervised in the community on probation or parole and those incarcerated in state or federal prisons and local jails. This was the first decline (down 0.7%) observed in the total correctional population since the Bureau of Justice Statistics (BJS) began reporting this population in 1980.1 This report provides summary data on the correctional population and highlights significant changes in the components of the population. Also, it covers adults supervised in the community or held in adult correctional facilities. The total prison population may include juveniles held in adult facilities in the six states with combined jail-prison systems."
Bureau of Justice Statistics: http://bjs.ojp.usdoj.gov/