Lucky people: 3-6 months
Unlucky people: > 15 months
Few people can get approval between in 7 months to 14 months.
If you get FBI quick by simple way ie computer, you should get GC in 6months. If further investigation is required, you may have to wait at least one year. The main reason for the delay is the backlog in FBI NC, especially for Chinese. You may have to wait 8-9 months to have a FBI official to review your case no matter how simple your case is. If your case is little bit complicate. Another waiting for the further investigation.