The nation’s incarceration rate peaked at 1,000 inmates per 100,000 adults during the three-year period between 2006 and 2008. It has declined every year since then and is now at its lowest point since 1996, when there were 830 inmates per 100,000 adults.
The number of inmates in the U.S. has also gone down in recent years, though not as sharply as the incarceration rate (which takes population change into account). The estimated 2,162,400 inmates who were in prison or jail at the end of 2016 were the fewest since 2004, when there were 2,136,600 inmates. The prison and jail population peaked in 2008 at 2,310,300.
A variety of factors help explain why U.S. incarceration trends have been on a downward trajectory. Crime rates have declined sharply in recent decades despite an uptick in the violent crime rate between 2014 and 2016, according to FBI data. As crime has declined, so have arrests: The nationwide arrest rate has fallen steadily in recent years and is well below where it was in the 1990s, according to BJS.
Changes in prosecution and judicial sentencing patterns, as well as criminal laws, also may play a role in the declining number and share of people behind bars. Recent reductions in prison sentences for thousands of inmates who were serving time for drug-related crimes, for example, have driven a substantial decline in the federal prison population. That, in turn, has contributed to the broader decline in the overall incarcerated population.
Despite these downward trends, the U.S. has the highest incarceration rate in the world, according to the World Prison Brief, a database maintained by the Institute for Criminal Policy Research at Birkbeck, University of London. The database compares incarceration rates across more than 200 countries and territories using publicly available data for each jurisdiction. (It’s important to note that the World Prison Brief’s U.S. data differ in some ways from the BJS data above. While BJS emphasizes the number of inmates per 100,000 adults ages 18 and older, for example, the World Prison Brief measures each country’s incarceration rate as the number of inmates per 100,000 people of any age. It also counts jail inmates in a slightly different way.)