Lets talk about this because it was a bone of contention between me and neonchameleon in another thread where he claimed FATE was the 2nd most popular roleplaying game next to the D&D games (Of course citing this chart as proof). First I'm curious... how do we compare the sales of these games? Because in September of 2013 both Numenera and 13thAGE ranked over FATE. I also think there is an inordinate number of discussions centered around FATE because there are alot of people trying to understand alot of it's jargon (aspects, invokes, compels, etc.) and concepts (Approaches vs. Stats for FAE)... but I could be wrong... so tell me what sales figures do we use to check these rankings?
Evil Hat have published sales figures before, though I don't think yet for Fate Core. But they told us how many copies of the Dresden Files RPG they printed, and that they had to have a reprint three months later. If IcV2 is in any way reliable, those 10,000 items got Dresden Files into 5th place in their RPG sale chart. Given that the Fate Core Kickstarter actually exceeded those numbers, I think we can assume that it is also selling rather well. Other companies seem less inclined to put sales numbers out, and I'm not prepared to put in the money to get a look at the Bookscan data - which anyway would cover few of the games in question.
Now this next bit is more speculative, but Fate Core had 10,103 backers; Numenara had 4,568; a ratio of 2.2 to 1. The Hot games list has them at 189 and 109, 1.7 to 1. I see little reason not to assume that there's about a 2 to 1 ratio of interest/play of Fate to Numenera; or to think that probably doesn't extend to purchases too.