There is no official data about number of subs. None. Even the "triple" part always comes back to the same source, which - again - is not an official one.
But then again, people were so eager to see WoW being dead, that they were willing to agree with statistics that would require 50% of playerbase to use Weak Auras in order to be true. Half of playerbase using addons - and a very specific one, that's generally linked to higher end raiding. Yep, totally a realistic scenario.
Yeah, that race to clear the Molten Core was heart pounding. Much harder than anything that happened on Retail. It was so close, especially the part with zero wipes and characters below max level.