There are 20 to 33 million marijuana users in the United States.
Each year, the federal government conducts a survey of Americans, called the National Survey on Drug Use and Health (NSDUH). The most recent data is from the 2013 survey, because it takes some time to process and release the results.
Three key questions are used to provide standard benchmarks on the number of marijuana users. Survey takers are asked if they have ever used marijuana, if they have used it in the last year and if they have used it in the last month. These last two questions are the basis for estimates of annual and past month users of marijuana.
Like any survey, NSDUH solicits data from a sample population and uses the results to estimate behavior in the total population of the country. It is one of the best social science surveys in the world, though the nature of the survey (targeting household populations and asking about illegal behavior) renders its results as minimum estimates. Nonetheless, it is the best and most widely available data.
Over 115 million Americans have used marijuana at least once in their lives, about 44 percent of the total population. The breakdown by age group shows that about 44 percent of those 35 and over have tried cannabis, but only 31 percent of 16- and 17-year-olds have tried it. From there, the percentage of use increase with age. Among 18- to 20-year-olds, it’s about 47 percent, 55 percent of those 21 to 25, and 57 percent of those 26 to 34.
This middle group of 18- to 34-year-olds is becoming increasingly significant in American elections, especially the presidential race. These young voters gave Barack Obama his election victory in the last two elections, and they are likely to be the swing voters in the 2016. The personal experience these voters have with marijuana, their familiarity with the actual effects of marijuana and their observations about marijuana use by friends and family is one of the driving forces behind changes in American attitudes about cannabis legalization.
In the last several decades a majority of Americans opposed marijuana legalization because they did not know much about the drug, and what they did know was usually propaganda spewed by law enforcement and government officials. As more and more Americans obtained direct knowledge about cannabis, more and more Americans rejected the misguided, ignorant and/or self-serving claims made by prohibition’s supporters.
The population estimate for annual users of marijuana—those who have used it at least once in the last year—is 33 million, about 12.6 percent of the total population. This breaks down to 25 percent of 16- and 17-year-olds, 35.3 percent of 18- to 20-year-olds, 30 percent of 21- to 25-year-olds and 21 percent of 26- to 34-year-olds. Only 6.5 percent of those 35 and older report annual use.
The population estimate for monthly users, or at least those who report using cannabis at least once in the last month, is 19.9 million. This breaks down to 14 percent of 16- and 17-year-olds, 21 percent of 18- to 20-year-olds, 19 percent of 21- to 25-year-olds and 12.5 percent of those 26 to 34. Only four percent of those 35 and older reported monthly use.
Two-thirds of annual marijuana users (22 million) only use marijuana—that is they do not use other illegal drugs. More interestingly, 80 percent of monthly marijuana users do not use other illegal drugs, 15.9 million people out of the 19.9 million total.
These are national estimates. The NSDUH also provide data on state-by-state marijuana use, though this is subject to a longer time-lag before data becomes available to the public. State level data is based on two years’ worth of data from the national survey. One of the most interesting, and awaited, results from upcoming survey reports is the impact of marijuana legalization on cannabis use in Washington and Colorado.
In 2003, there were 26 million annual marijuana users in the United States, about 10.8 percent of the population. Now that figure is up to 33 million, 12.6 percent, and likely will continue to rise. It may be that more people are willing to be honest with the national survey, but it is also likely that more and more people have decided that marijuana has value for them.
Marijuana use is increasing because people know more about it first-hand from experience and/or by learning about it from credible sources. Regardless of why use is increasing, the wide-spread familiarity with marijuana among young adults is causing a political revolution that makes the legalization of cannabis more likely in the near future than ever before.