Thanks!
A useful link.
Here's more from a detailed report at that same site:
At yearend 2004 (the most recent data available for estimating offense distributions by gender and race) more than half (52%) of all sentenced inmates in State prisons were sentenced for a violent offense (table 11) (See Appendix tables 9 and 10). Property offenses were the most serious charge for 21% of State prisoners, and drug offenses, 20%.
...On September 30, 2006, (the latest available data from the Federal Justice Statistics Program on offenses of Federal prisoners) drug, weapons, and immigration offenders made up more than three-quarters (78%) of the 176,268 sentenced Federal prison population (table 12). Drug offenders made up more than half (53%); weapons offenders, 14%; and immigration offenders, 11%.
What I'm seeing here is that most of the offenses are not drug related. There are far more State prisoners than Federal ones, so the high Federal percentage of drug offenses doesn't tilt it much. If you combine the two populations, the drug offenses come to 24 percent.