Upvote:3
The 40,000 figure comes from a chart that is quoted by the "Best Estimates" web site, the estimation comes from the a chart that is linked below originally provided by Gordon Conwell Edu. It is an estimation of where things stand now in Christianity world wide. This figure is actually off now, and has been surpassed as time has passed. If you go to line 41 of the original chart the figure should now be over 45,000 separate denominations, and should grow to 55K by 2025!