Table 1 contains the distribution of perceived risk of regular cannabis use in each survey year, prior to dichotomization. After dichotomizing the perceived risk variable, the percentage of participants who perceived a great risk associated with regular cannabis use varied significantly between 2002 and 2012 χ2(10, N = 607,324) = 109.81, p<0.001. In 2002, 51.3% of NSDUH participants perceived a great risk associated with regular cannabis use, versus 40.3% of participants in 2012. This 11.0% decrease was statistically significant, χ2(df=1, N=108,026) = 341.40, p<0.001 (Table 2). Similar variation across the decade, and significant decreases in perceived great risk were observed for all other race/ethnicity and age categories in the full sample, with the following exceptions where significant variation between 2002–2012 was not observed: participants of Other race/ethnicity age 26–49 χ2(10, N = 11,641) = 2.87, p=0.004 and age 50+ χ2(10, N = 3,267) = 1.92, p=0.051.
