On average, half of all police officers convicted as a result of FBI-led corruption cases between 1993 and 1997 were convicted for drug-related offenses.

Source

General Accounting Office, Report to the Honorable Charles B. Rangel, House of Representatives, "Law Enforcement: Information on Drug-Related Police Corruption" (Washington, DC: USGPO, May 1998), p. 35.
http://www.gao.gov/products/G…