I don't know if I understood you well... are you talking about how many PCs are lurking in our community websites, or how many real humans are Anima players ?? We probably can ask on the forum for the first, but the second, I think I really didn't understand what you mean...
But if it can help you, I Master 2 regular groups and one from time to time, both the regulars each contain 4 PCs, and the third, 5.