Slightly under 1.5 million people were in prison at the end of 2017, a population that if gathered in one place would be one of the largest cities in the country. Still, this was a decrease of 1.2% from 2016, and a nearly 8% drop from the peak of prison population in 2009. County and city jails held around 750,000 inmates in mid-2017.
Combined, this would make the United States by far the world’s leader in incarceration according to data collected by the Institute for Criminal Policy Research at Birkbeck, University of London, though it is unclear exactly how many people are held in detention in China, the country with the second highest count.
A drop in the federal prison population accounts for a third of the year-over-year decline, and while some states have significantly reduced their prison populations in recent years, others continue to set records for the number of people they are keeping locked up. Given that crime rates have fallen across the nation over the past decades, this unevenness is almost entirely because of policy changes and court orders.
“Crime rates have been declining for 25 years now pretty much across the board,” said Marc Mauer, the executive director of the Sentencing Project, a group that advocates for improvements to the criminal justice system. “One might ordinarily think this should have led to a substantial reduction in the prison population.”
Instead, he said, “what we see is that a moderate number of states have achieved substantial reductions of 30% or more, but most states have only experienced a very modest decline and some states have still been increasing their population.”
This article originally appeared in The New York Times.