It may be bad form to even think about this question, but reading through some of the Fun Trivia Player Statistics has made me wonder.
Up through the Adept player level, some players have ratings as high as 99%. At 500 quizzes attempted, this would be about 5,000 questions, with only 50 to <100 incorrect. Another way of looking at this would be 400 to 450 perfect 10/10's.
If I wrote 500 quizzes and went back to play them (i.e., my own), I think I would be doing well to get that percentage.
My own accuracy after 436 quizzes is 68%; nothing to brag about, I admit, but it does make a 99% rating seem beyond what is possible.
Is there some other explanation for this phenomenon besides my own mediocrity?