As for those who vehemently say they never touched this stuff, well, you would say that if you were in the aviation industry wouldn't you? How could we know? You must have lived a very sheltered life.
I remember discussing this subject with my local GP in an extremely nice part of Melbourne. He told me that there would not be one street in Toorak, Armadale and Malvern that didn't have at least one heroin addict in it. As for marijuana use amongst private schools, it's out of control and has been that way for at least ten years. Then of course there is the club scene with extacy and ice.
As I said before, Dope and other drugs are easier for a kid to acquire than cigarettes and alcohol, and I'm speaking from very bitter, expensive and personal experience in having to deal with the consequences of this stuff as a parent. As I said, I don't believe that there are any teenagers who haven't tried it - and that comes from experience.