Attitudes Regarding Legality of Marijuana Use: Trends in 12th Graders

(Percentages saying "yes", i.e. supporting legal prohibitions)
  1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019   2018 -
2019
Change
  2014 -
2019
Change
Proportional
Change
  Peak year -
2019
Change
Proportional
Change
  Low year -
2019
Change
Proportional
Change
Use in public 12th Grade 27.5 26.7 25.4 28.0 28.9 35.4 36.6 37.8 41.6 44.7 43.8 47.6 51.8 51.5 56.0 51.6 52.4 48.0 42.9 44.0 40.4 38.8 39.8 39.3 38.8 39.1 38.4 40.3 41.4 40.7 42.3 38.7 39.3 36.7 32.8 34.2 33.0 32.0 28.5 26.5 23.8 22.9 21.7 20.5 | -1.2 | -7.9*** -27.8 | -35.5*** -63.3 | 0.0 0.0
Use in private 12th Grade 59.1 58.7 59.5 61.8 66.1 67.4 72.8 73.6 75.2 78.2 78.9 79.7 81.3 80.0 81.9 79.8 78.3 77.3 72.5 72.9 70.0 69.4 72.2 71.5 72.1 68.3 67.6 68.6 69.2 69.6 68.5 69.4 70.2 67.1 62.4 63.8 64.4 61.3 57.0 55.7 57.0 50.3 47.9 49.1 | 1.2 | -8.0*** -13.9 | -32.8*** -40.1 | 1.2 2.5

Source: The Monitoring the Future study, the University of Michigan.
"Do you think that people (who are 18 or older) should be prohibited by law from doing each of the following? Answer alternatives were: (1) No, (2) Not sure, and (3) Yes.
The year with the highest percentage of those saying "Yes" is noted in bold. The year with the lowest percentage after that peak is underlined.
For a table of Ns click here: Notes
*** = p < 0.001 ** = p < 0.01 * = p < 0.05