Food service workers are the biggest potheads, according to a new study.
Researchers quizzed more than 10,000 people in Colorado, where recreational marijuana use is legal, on their smoking habits.
Almost 15 percent admitted smoking at least once in the previous month, but for people employed in 'food preparation and serving' jobs, it was 32.2 percent - almost one in three.
Close behind were people employed in 'accommodation and food services' at 30.1 percent, and arts/entertainment workers, at 28.3 percent.
The researchers say the high figures could be because of the high - no pun intended - prevalence of young people in the accommodation and food service industries.
People aged 18-25 had the highest rate of marijuana use at 29.6 percent, compared to only 11 percent for people 35 and older.
Other jobs with higher-than-average marijuana use included construction, real estate, retail and manufacturing.
Low rates of toking were found in transportation, teaching, mining, oil, gas and social work, perhaps because employers in these industries routinely test for drug use.
Non-Hispanic whites had the highest rate of marijuana use, followed by Hispanics, then African-Americans.
The study was carried out by the US Centers for Disease Control.