You're incorrect about the methodological flaws. Only 50-year-olds are mentioned because this is a longitudinal cohort they've been testing since 1977, and thi

You're incorrect about the methodological flaws. Only 50-year-olds are mentioned because this is a longitudinal cohort they've been testing since 1977, and this year (2009) it's their turn to be reported. The "adjusted" number is higher than the measured number because some people answered the survey ten years ago saying they'd tried marijuana in the past year but then in the current survey the same respondent said "no" when asked if they'd ever tried marijuana in their lifetime. So they're publishing both the actual numbers and the "we know you're probably lying" numbers.