I do not know if there are any figures available other than prosecutions on the likely numbers of pilots who probably have flown while slightly over limit?
I am sure most of us at some time in the past have driven home from a pub or party thinking that they were probably under and would risk it.
I am sure if there was a police car parked at the entrance to the pub no one would get into that car if there was any doubt at all.
IT could be the case of doing something stupid the night before rather than an alcoholic with a drinking problem but this something stupid will ruin your career and reputation
obviously a seriously drunk pilot will be noticed by other crew or security but those just over probably won't
Pilots are not super Gods and due to the nature of their jobs are probably more likely to suffer personal problems and as posted Fatigue and stress is more likely to create a situation where a one off indiscretion could have disastrous results for the pilot and possibly safety of the aircraft