Lifetime use of marijuana is 44% but past month use of illicit drugs other than marijuana is only 3.3% - pretty narrow "gateway". (http://www.samhsa.gov/data/sites/default/files/NSDUH-DetTabsPDFWHTML2013/Web/HTML/NSDUH-DetTabsSect1peTabs1to46-2013.htm#tab1.1b)
Did you know every significant male in history was "gay"? I don't either, but if you hear them tell it they were.