At this moment, we've had 42125 members join since 1/1/2004. The ~12000 difference is due to the regular pruning of members for various reasons such as never completing the registration process, not visiting for years (deleted only if they have never posted), etc. But the majority of those 12000 are spambot registrations. You never see them because they never complet email verification, or they're caught by the spam wolves if they make it past the alligator moat. (We actually get about 50000 spambot registration
attempts per year, but we have some software that never lets them get through the registration process.)
Probably more than you wanted to know