Percentage of high school seniors reporting they could obtain drugs easily in 2006:

Marijuana 84.9%

Amphetamines 52.9%

Cocaine 46.5%

Barbiturates 43.8%

Crack 38.8%

LSD 29.0%

Heroin 27.4%

Methamphetamine 26.7%

Tranquilizers 24.4%

PCP 23.1%

Amyl/butyl nitrites 18.4%

Source: Press release, "Teen drug use continues down in 2006, particularly among older teens; but use of prescription-type drugs remains high," University of Michigan News and Information Services, Dec. 21, 2006.

Drug use in the general population

According to data from the 2006 National Survey on Drug Use and Health:

• 112 million Americans age 12 or older (45 percent of the population) reported illicit drug use at least once in their lifetime.

• 14 percent reported use of an illicit drug within the past year.

• 8 percent reported use of an illicit drug within the past month.

• Data from the 2006 survey showed that marijuana and cocaine use is most prevalent among persons 18 to 25.