Ten years ago it was about 9-12 months. Today, no idea but Bunk22 might have some insight on who might be on the board and could help with that question.
Back then it was about 2 months of ground school/sims and then on to the squadron for 13 hops. A few additional hops for CQ which depending on aircraft availiblity and carrier schedules would come very quickly or painfully slow.
I'm sure though with the invention of NAPP that they have decreased that by the optimum 25% Time to train. Yea right.