Did you know the "population" of JetPunk, that is number of accounts that have ever been made, is about the same as the population of Botswana?
Here's a quiz I recently made by which I came to realize this interesting observation: Countries whose Population is Smaller than JetPunk
Do you have the number of active accounts, just to compare?
On the other hand, a majority of visitors don't even have accounts at all!
So the real number of users is probably much higher. It's really impossible to say, but if I had to guess I'd say at least 10 million people have taken at least 1 quiz.
For example, I have had students use JetPunk before (I know others such as Dimby have too). Most of them don't end up making accounts. I could see it being much higher than 10 million!