I actually have a different version to this: 9X% of everything is crap, where X ranges from 0 to 9.999. That variation though is what differentiates a category and a time, since either 1 in 10, in 100 or 1 in 1000 can be a great find.

This is the reason why movies or music seemed better in other times, because X was close to 0 then and now it's 9.