Gallup said a clear majority of Americans -- 58 percent -- say marijuana should be legalized, a 10-point jump over the past year.
In 1969 -- the first time Gallup asked the question -- only 12 percent favored legalization. By the 1970s the figure was 28 percent, and it reached 50 percent in 2011.
Thirty-eight percent of respondents said they have tried the drug.
A whopping 67 percent of Americans ages 18-29 support legalization, while those 65 and older are the only age group still opposing such a measure, Gallup said.
The poll of 1,028 adults ages 18 and older, conducted Oct. 3-6, has a margin of error of 4 percentage points.