So a bunch of people who fail on their first attempt, and they pass the second (or third) time. So, of all people who eventually pass, 70-80% took the test twice or more.
Corollary: in any given exam, 20-50% of all exam takers are there for the second (or more) time. So the total number of first-timers is considerably less than 100% and I’m guessing that their failure rate is greater than 50%.