I think I can reasonably state a tiny book like a Nojuice had a few hundred, so Pinny must be at least 100X that for say 30,000, but it could easily be way more.
How many accounts get created, and go unfunded, or are only briefly active ? Pinny accounts are probably much more likely to be active, than accounts at places with big bonuses, those that are active about 2 days, then die.