what is the equivalent percentage in the same age range in civi life? oh we don't know as only a tiny fraction of them are tested.
I was involved in a the testing process a while ago - certain people were 'randomly' chosen as there was good reason to test them above others in the Regiment.
Every recruit is tested at least once in basic training - it was normally in the first few days of arrival. It wasn't uncommon at all to get admissions of various recreational drugs being used, some tried to bluff their way through it.
One lad had his 'mates' write a letter confessing that they had fed him hash cakes without his knowledge. He was retained but was under no illusion as to where he'd be going if he delivered a positive sample again.
Civil airline pilots are about as good a reference point I can give you.
They also take calculated risks, if you get where I'm going. As do surgeons, Judges, GPs, Lawyers... Just about anyone with a social life in this era!