“Nearly 300,000 people are held in state and federal prisons in the United States for drug-law violations, up from less than 25,000 in 1980. These offenders served more time than in the past: Those who left state prisons in 2009 had been behind bars an average of 2.2 years, a 36 percent increase over 1990, while prison terms for federal drug offenders jumped 153 percent between 1988 and 2012, from about two to roughly five years.“