Aging Behind Bars America's prison population has aged significantly, increasing the costs of incarceration. These four inmates show just some of the challenges older inmates bring. Andrew Burton | April 2015 Like the rest of America, the national prison population is growing older. Approximately 16 percent of prisoners today are over age 50; the number of inmates 55 and over increased nearly 1,400 percent from 1981 to 2012, according to the American Civil Liberties Union. Thanks mostly to increased health-care expenses, states spend nearly twice as much on incarcerating older inmates as they do on average prisoners. In December 2013, photographer Andrew Burton documented the lives of aging prisoners at several correctional facilities, including two prisons in California and one in Rhode Island. His photos and captions indicate some of the challenges states face in housing this special population of prisoners.