(1980-2009 - Total, marijuana and drug arrests by year) Although the intent of a ‘War on Drugs’ may have been to target drug smugglers and ‘King Pins,’ over half (51.6%) of the 1,663,582 total 2009 arrests for drug abuse violations were for marijuana — a calculated total of 858,408. Of those, an estimated 758,593 people (45.6%) were arrested for marijuana possession alone. By contrast in 2000, a total of 734,497 Americans were arrested for marijuana offenses, of which 646,042 were for possession alone.
http://www.drugwarfacts.org/cms/Marijuana#Share