It's 45K according to the post just above yours.
And, yes, that is very ambitious for QPR.
But they are based in a densely populated, relatively prosperous district in the biggest metropolitan area in western Europe. If QPR have got serious ambitions to grow, good for them.
Just to add, as I said on the other thread in the stadiums section of SSC, once this and Spurs' and Chelsea's new homes are built, London will have an incredible selection of stadiums.
36k seems too ambitious to me, theres no way they would get those numbers unless it was maybe a £5 to get in against man utd.