RFE responce time _ California center

My Employer filed my H1 B transfer on Jan 19th 2015 and got RFE on Feb 25th 2015. USCIS received my RFE documents on April 30th 2015. after that the status changed to “Response To USCIS’ Request For Evidence Was Received” today is July 21st ( more than 90 days)… still waiting.
kindly share your experience, how much time it will take to get a decesion ?