oooh that graph is really cool... I'd forgotten Google could do that. I'm not convinced anything has changed with the NYT takeover really myself.I definitely have used my third guess more. I don't recall ever having used to actual answer. In the usage chart from Google books, blue is our initial guess and red is the actual answer.
I do think pre NYT you could more reliably use the more common word, now it seems they purposefully go for niche words.