Mandatory minimum penalties continue to have a significant impact on the size and composition of the federal prison population

"• As of September 30, 2016, 49.1 percent of federal inmates were drug offenders.

"• Among drug offenders in federal prison as of September 30, 2016, almost three-quarters (72.3%) were convicted of an offense carrying a mandatory minimum penalty, and more than half (50.4%) remained subject to that penalty at sentencing."

Source

"Mandatory Minimum Penalties for Drug Offenses in the Federal Criminal Justice System," US Sentencing Commission, October 2017.