Gallup: A record-high 50% of Americans now say the use of marijuana should be made legal, up from 46% last year. Forty-six percent say marijuana use should remain illegal. When Gallup first asked about legalizing marijuana, in 1969, 12% of Americans favored it, while 84% were opposed. Support remained in the mid-20s in Gallup measures from the late 1970s to the mid-1990s, but has crept up since, passing 30% in 2000 and 40% in 2009 before reaching the 50% level in this year's Oct. 6-9 annual Crime survey.