It was in OS X Lion. Apple's since removed the page, but it is saved in the internet archive.[0]
> "Lion offers over 3,000 new APIs covering a range of new technologies and capabilities."
[0] http://web.archive.org/web/20130425175054/https://developer....
I think Apple meant new methods, classes and possibly even the options that you could pass as arguments.
Whatever it means I don't think that more is necessarily better and I hope no one has adding APIs as a performance metric!