A Pew study shows that sentences for Americans convicted of federal drug crimes rose 36% — an average of 20 months — in 30 years, while sentences for all other offenders in federal prison declined by 3%. Pew says "the increased imprisonment of drug offenders has helped drive the explosive overall growth of the federal prison system, which held nearly 800 percent more inmates in 2013 than it did in 1980." The jump in inmates has led to huge amounts of increased spending. From 1980 to 2013, federal prison spending increased 595%, from $970 million to more than $6.7 billion.