all 3 core books made it to the top 100 on the RPG product list at BGG within 2 mounths of their release.
#100 DMG
#48 MM
#5 PHB
http://boardgamegeek.com/browse/rpgitem/page/1?sort=rank
I'd be more impressed if BGG ratings meant something. Not trying to be snarky, I'm just saying I literally have had meetings with the guy who runs that part of BGG and we've been trying to figure out how to make those numbers mean something. They're not an aggregate mean of user reviews, or a measure of game popularity and instead the result of a very byzantine system based on the BGG community members who give input on it. ENWorld's hot game chart is probably a better indicator of present relevance. And of course 5e is #1 there at the moment, but a lot of that is people, ironically, debating its relevancy. 