Marijuana is gradually becoming the drug of choice among young adults in the U.S., while use of methamphetamines is subsiding, according to a national survey on drug use released on Thursday.

Almost nine percent of the U.S. population -- translating to 22.6 million people aged 12 and over - used illicit drugs in 2010, up from 8.7 percent in 2009 and eight percent in 2008, according to a survey by the Substance Abuse and Mental Health Services Administration. The findings revealed Americans are partaking in a variety of illegal substances, ranging from recreational prescription drugs to hallucinogens, cocaine, heroin, marijuana and inhalants.

According to the survey, marijuana is by far the most popularly consumed drug. There are reportedly 17.4 million regular users in the nation. Nearly seven percent of the population indulged in pot in 2010, up from 5.8 percent in 2007.

However, the rise in marijuana use doesn't necessarily mean there are more recreational smokers. Gil Kerlikowske, the director of the Office of National Drug Control Policy, said increases are prominent in states that have legalized medical marijuana.

Emerging research reveals potential links between state laws permitting access to smoked medical marijuana and higher rates of marijuana use, Kerlikowske said in a statement.

While more people may be partaking in Mary Jane, the survey found that use of virtually every other illegal substance is falling. The number of meth users fell by about half between 2006 and 2010, to 353,000 last year from 731,000 in 2006.

Meanwhile, cocaine use also dropped significantly -- from 2.4 million in 2006 to 1.5 million in 2010 -- while alcohol consumption among minors fell from 14.7 percent in 2009 to 13.6 percent in 2010.

Still, the survey found that many Americans are suffering from substance abuse issues, but may not know it or have access to help. Of the 23 million Americans in need of rehabilitation treatment in 2010, fewer than three million reportedly received it.

There were 30,922 drug-related arrests made across the nation last year, according to the U.S. Drug Enforcement Administration.  In February, the Drug Policy Alliance reported there were more arrests in New York City on charges of marijuana possession in 2010 than during the entire 19-year period from 1978 to 1996.