How do you have this 5 number they haven't released that information for a long time and the last time they did was when it surged up during WoD. If the games population followed these growth cycles or as you are calling it a curve it would have died off over 5 years ago. If nothing else they have found a way into playing the game more since you can buy all of their other stuff with tokens now. So not only have they baited more people in to turn other content into f2p or f2b, they got somebody else to give them extra money to allow those people to do that.