It is undisputed that marijuana is and has been widely available throughout the United States since the 1970s. Reports cited above indicate that over the last 20 years there was been a minimum of 8,000 mt or 17.6 million pounds of marijuana available annually for US consumers.

The 2003 Library of Congress report presents data from a 2001 National Drug Threat Survey (NDTS) of the National Drug Intelligence Committee (NDIC)(22) which reports:

"that 96.9 percent of state and local law enforcement agencies nationwide describe the availability of marijuana as high or medium; only 1.8 percent describes it as low. From region to region, the proportions of agencies reporting high or medium availability were very similar and ranged only from 98.9 percent in the Mid-Atlantic region to 91.6 percent in the Florida/Caribbean"(23)

Table 6 presents data from the National Survey on Drug Use and Health (formerly the National Household Survey on Drug Abuse) on the availability of marijuana from 1991 through 2005, by age group. On a percentage basis this table indicates how many people reported that marijuana was "fairly easy" or "very easy" to acquire. During this period, in an average year 54.81% of 12 to 17 year olds reported that marijuana was easy to get. Marijuana was most available to 18 to 25 year olds, 77.45% of which reported it was easy to get in an average year. Of 25 to 34 year olds in an average year 67.47% found marijuana easy to get, while only 52.24% of those 35 and over found marijuana easy to acquire in an average year.

Overall, from 1991 to 2005 in an average year 58.44% of the public found marijuana readily available. Over the last several years the percentage of the 12 to 17 year old age group finding marijuana easy to get has declined, from 57.9% in 1997 to 50.9% in 2005. However, during the same period availability to 18 to 25 year olds has remained essentially unchanged, 77% in 1997 to 76.5% in 2005.

Monitoring the Future (MTF) is an annual survey conducted by researchers at the University of Michigan, and it has collected data on the availability of marijuana to 8th, 10th, and 12th grade students. (See Table 7.) The MTF data also reports declining availability of marijuana to 8th, 10th, and 12th graders over the last 10 years. Among 8th graders the percentage reporting marijuana was easy to acquire has declined from 54% in 1997 to 40% in 2006, while among 10th graders this percentage has declined from 80% in 1997 to 70% in 2006. Among 12th graders this percentage has declined from 89% to 85% in this same period.

Two trends in the MTF data, though, remain unchanged over the years. First of all, as students enter 10th and 12th grade more and more of them find marijuana easy to acquire. Second, from 1975 to the present at least 4 out of 5 high school seniors report that marijuana is fairly easy or very easy to get.

Regardless of annual changes in this survey data, since 1992 these surveys report that at least 2 out of 5 eighth grade students, 2 out of 3 tenth grade students, and 4 out of 5 high school seniors find marijuana widely available.

One of the reasons marijuana is so widely available to high school students is that many students sell marijuana to one another. The National Survey on Drug Use and Health, in addition to drug use and availability, also tracks the prevalence of individuals who sell drugs. In the 15 years from 1991 to 2005 the number of 12 to 17 year olds who have sold drugs in the last year has increased 90%, from 429,169 in 1991 to 814,924 in 2005, reaching its greatest level in 2002 at 1,080,549. (See Table 8.)

While these figures indicate sales of any illicit drug there is a strong likelihood, given marijuana's widespread popularity and overall availability, that most of this sales activity involves marijuana. Overall, the number of individuals of any age who reported drug selling activity doubled from 1991 to 2005. The number of individuals increased during this time from 1,783,863 in 1991 to 4,535,825 in 2005, and the corresponding percentage increased from .9% to 1.9%.

Data on the extent of marijuana use by students and other age groups will be reviewed in greater detail below. However, a comparison of the number of monthly users of marijuana between the ages of 12 and 17 with the number of drug sellers in the same age group reveals a significant characteristic which might explain the persistent prevalence of adolescent marijuana use.

According to the 2005 National Survey on Drug Use and Health there are 1,728,265 monthly users of marijuana in this important age group of 12 to 17 year olds. The number of adolescents in this group who have sold drugs represents almost half of the number who have used marijuana in the last month: 814, 924 or 47%. On a percentage basis, 6.8% of adolescents report using marijuana in the last month and 3.2% of adolescents report selling drugs in the last year. These figures suggest that teenage drug sales is one of the key factors that explain both the widespread availability and usage of marijuana to middle and high school students.