According to Eric Musco at the latest Cantina meet and greet event: "over 10 million play occasionally, while over 1 million play per month."
Now, that definition is pretty loose, and we all know that number of players doesn't really matter for a game that has a free to play option, but I think we can stop saying 'lul game is ded" now. As far as I know he also did not specify if that was Western only or World wide. I am inclined to believe it is West only, because when they used to give sub numbers it was always West only.