M.T. Black states the following, which as Dancey says is within spittingdistance of
@BenRiggs Estimate:
"If we fast forward to the famous Adventure Game Industry Market Research Summary released by Wizards of the Coast in the year 2000, we see they estimate the number of people in the United States playing any tabletop roleplaying game at least monthly to be 2.25 million, with a total number of 5.5 million having ever played a tabletop roleplaying game."
This article presents an estimate of the number of people currently playing Dungeons & Dragons around the world and also discusses historical estimates.
www.mtblackgames.com