A new report shows just how much the war on drugs fundamentally changed the scope of the federal prison system — without any significant benefits to show for it.

The report from Pew Charitable Trusts found the number of federal prisoners serving time for drug offenses skyrocketed by more than 1,800 percent between 1980 and 2015 — from fewer than 5,000 to more than 95,000.

These prisoners are also serving much longer sentences, according to the report. While sentences for non-drug offenses declined by 3 percent from 1980 to 2011, sentences for drug offenses spiked by nearly 36 percent in the same time period.

After they were sentenced, the average time released drug offenders spent in prison increased 153 percent between 1988 and 2012 — from 23.2 to 58.6 months — while time served grew by 39 and 44 percent for property and violent offenders.

The sentencing and time spent figures differ because prisoners can have their sentences reduced for good behavior or, if they were convicted prior to November 1987, be released early on parole after serving part of their sentences.

Although these stringent sentences were originally meant for some of the worst drug offenders, the Pew Charitable Trusts report found that they're by and large picking up low- and midlevel traffickers. It estimated, based on federal data, that high-level suppliers and importers represented just 11 percent of federal drug offenders.

The Pew Charitable Trusts report concludes that this increase in incarceration and time served came with high costs and little returns. Drug offenders currently make up nearly half of the federal prison population, and the federal prison system now uses up roughly one in four dollars spent by the US Justice Department. Drug use, meanwhile, appears to have steadily risen over the past two decades, according to the nationwide surveys.

But the federal prison system is very different from the larger state prison system, which houses more than 86 percent of the US prison population. About 54 percent of state prisoners were violent offenders in 2012, while 16 percent were drug offenders, according to the Bureau of Justice Statistics. So cutting sentences for drug offenses would help reduce the federal prison population, but decreasing the number of state prisoners will likely require reducing sentences for violent crimes, too.

Still, the Pew Charitable Trusts report puts the war on drugs in very stark terms: Federal lawmakers put a lot of money toward the drug war with the passage of anti-drug laws throughout the 1980s, and they have very little to show for it decades later.