"Violent offenders under Federal jurisdiction increased 46% from 1995 to 2003, and accounted for almost 8% of the total growth during the period. Homicide offenders increased 146%, from 1,068 in 1995 to 2,632 in 2003.
"While the number of offenders in each major offense category increased [from 1995 to 2003], the number incarcerated for a drug offense accounted for the largest percentage of the total growth (49%), followed by public-order offenders (38%)."
Source
Harrison, Paige M. & Allen J. Beck, Allen J., PhD. Prisoners in 2005. Washington: DC: US Department of Justice, Bureau of Justice Statistics. Nov. 2006. NCJ 215092.