How many Everest climbers are there?

At least 2,700.

There have been at least 2,700 Everest climbers since 1953. This is based on the Everest Ascents list of summits made from May 29, 1953 to May 28, 2008 made by Eberhard Jurgalski. In the 2009 climbing season 37 teams attempted to summit the mountain, with at least 338 persons (with an indiscernible number having reached the summit before) making it to the summit. This is according to data compiled by Alan Arnette.