More than half of US federal prison inmates are in jail for drug trafficking, with the harshest sentences going to crack dealers, most of them African Americans, a study finds.
The federal prison population increased by 84 percent between 1998 and 2012, due largely to a crackdown on drugs, according to a study by the Bureau of Justice Statistics.
The report comes as America, whose incarceration rate is the highest among developed countries, grapples with the harsh policies that have seen petty criminals and drug users sentenced to long prison terms for minor, non-violent offences.
Some 52 percent of inmates were in jail for a drug offence as their most serious crime, according to the study, which was based on 2012 data.
More than half (54 percent) of those inmates were in jail for cocaine – either in the form of crack (28 percent) or powder (26 percent).
Sentences for methamphetamines were next at 23 percent, followed by marijuana (12 percent) and heroine (six percent).
Black people represented 88 percent of crack cocaine offenders, while Latinos accounted for 54 percent of powder, or cocaine, offenders.
Whites made up 48 percent of methamphetamine offenders.
The average drug offender prison sentence was more than 11 years, but crack offenders received harsher punishment, with an average of 170 months (more than 14 years).
The study, which was based on 94,678 federal prison drug offenders, also indicated that crack offenders had a greater tendency to have extensive criminal histories and use weapons.
More than a third of inmates sentenced for drug offences had a minimal criminal history or no prior run-in with the law.
Just last week, a group of 130 police chiefs, prosecutors and sheriffs from around the United States called for reforms that would reduce the US prison population, a move also backed by President Barack Obama.
The United States is preparing to release in November thousands of prisoners considered at low risk of returning to crime, as part of an effort to ease prison overcrowding and redress overly harsh sentences.
The release comes after the US Sentencing Commission, which sets policy for federal crimes, reduced its sentencing guidelines for drug possession.