Yeah I think this 5% is way too overrated. Of course from who do you take this percentage? Some may not count beginners as students and count that percentage from ppl who reach sempai status (3rd kyu at least). From all students who have ever been in our dojo the count would be zero
200 ppl over 5 years and only sensei has black belt. Although it may be predicted that by the time the count reaches 300 and a couple of years from now on, it'll be somewhere between 3 and 6 shodan. So 1-2%. 10+%???? You must be kidding...