No one knows! It's one of the well-kept fanpop secrets!
Though it's probably quite a few votes, since not to many perguntas have 'best answers'. I suspect it to be at least 10, but that's just guesswork. Also, I think a lot of people don't vote much, even if they find a good answer.
i voted THIS as best answer :P i think it takes a while and would even up that...it might be a calculation of "answers given" and "votes" so chances are there is no absolute number