After reading/posting here to two years, I think the 6-8 months assuming you are paper ready is probably the "norm," if there is such a thing.
My daughter was 2.5 months at referral and came home at 11 months - so 8.5 months in process.
My son was 11.5 months at referral and came home at 20 months - so again about 8.5 months.