I've not tried to keep any such records. I'm not sure if Matt has some way to pull such data from the logs and such he has access to or not. He and I do have access to the full list of members and from that I think could figure it but it would mean many hours of work and for sure I'm not gonna put in the amount of time it would take.
What I can tell you for sure is we closed out 2005 with about 14,750 or so members. We've already crossed the 19,100 mark for 2007 and should wind up over 19,200 for sure so we'll add about 4500 this year alone. If the present growth rate continues I expect to close out 2007 with over 25,000 registered members.
In November of 2002 when we changed from the original cascading software that Matt wrote for our use we had to get everyone to register again in order to use the phpbb software. So beginning on Nov. 20, 2002 the current list began. Since then there have been over 19,100 members register.
That's about the best I can do for stats at this time.