This is the timeframe USCIS is giving, depending on each service centers:
California: Not listed
Texas: Currently processing cases from May 7, 2015 (That can't be right...)
Nebraska: 3.5 months
Vermont: 3.5 months
I'm with Nebraska, so it makes sense... I sent mine on 04/04, so I would probably get it on 07/19+ (cutting it close with my exp. date on 08/16, but w/e).
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(Application done by myself) Date delivered - 8/16/12 Nebraska
Date acceptance letter of application received - 8/20/12
Date of I-797 C Notice of Action (Application Approved) - 8/21/12
Date Biometrics scheduled - 9/12/12
Date of EAD Notification- 9/28/12