Drug Use by People in Prison at the Time of Their Offense

"Violent offenders in State prison (50%) were less likely than drug (72%) and property (64%) offenders to have used drugs in the month prior to their offense."

Source: 

Mumola, Christopher J., and Karberg, Jennifer C., "Drug Use and Dependence, State and Federal Prisoners, 2004," (Washington, DC: US Dept. of Justice, Oct. 2006) (NCJ213530), p. 1.