http://www.online-golf-lesson-and-more.com/world-golf-statistics.html
Roughly speaking:
scratch (or 70s) < 1%
+single digit (or low 80s) < 5%
+bogey players (or high 80s) < 15%
+under 100 players ( or 90s) < 30%
If you are in any of these brackets, pat on your own shoulder :)