Li Kao wrote:@Kirk
I think you need to ignore the 2011 number. It probably just doesn't compensate for the fact that it only counts the first few months of 2011. If you multiply it by 12/3 you're around 1600, which seems normal. The 2009 drop isn't that big.
I'd guess the graph contains the number of distinct players who took part in a tournament. But while I found the graph on the aga db website, I found no explanation of how they define an active player.
I thought the 2011 number was based on dues-paying members or something. So, to be fair, they're irresponsible in publishing a number like that; or at least it has little or no value until the end of the year.