The U.S. has long had the unenviable distinction of holding the world's largest prison population, thanks in part to tough-on-crime policies enacted in the 1990s. But sentencing reforms passed in recent years appear to have made a dent, leading to declines over the past eight years.A criminal justice reform organization reported Friday the U.S. prison population dropped below 1.5 million for the first time in more than a decade last year.According to the Washington-based Vera Institute of Justice, the decline was driven by a sharp decrease in the number of inmates in federal prisons and decreases in several states with large prison populations.The total U.S. prison population dropped to 1,486,000 last year, a decline of nearly 20,000, or 1 percent. The number of prisoners in federal prisons and detention centers dropped 3.1 percent to 183,000 and the number of inmates in state prisons declined by 0.7 percent to 1.3 million, according to the report.The decline extended an eight-year-long downtrend in the U.S. prison population, driven by federal and state sentencing reforms enacted over the past decade. But the Vera institute cautioned it's unclear if the trend will continue."Whether criminal justice reform can continue to fuel this sustained decline in the prison population remains to be seen," said Jacob Kang-Brown, Senior Research Associate at Vera. "We must continue to do the hard work, as advocates and agents of change, to ensure that all our communities feel the relief of decarceration." The report came as U.S. President Donald Trump called on Congress to enact prison reform legislation to help former inmates re-integrate into society and reduce the rate of recidivism among felons."We want former inmates to find a path to success so they can support their families and support their communities," Trump said at a White House summit on prison reform. "Crucial to this effort is helping former prisoners find jobs."More than 620,000 inmates are released from prison annually, with about 50 percent of the prisoners released from state prisons returning to prison within three to five years, according to the National Criminal Justice Reference Service."Nobody wins when former prisoners fail to adjust to life outside, or worse, end up back behind bars," Trump said. "We want former inmates to find a path to success so they can support their families and support their communities."