It takes around 12 years as of today, might get worse..
search for it on google. i did it a few days back and saw folks in this last family based immigration category, who applied in 1996 are current now to get a immigrant visa number. Assuming 6 months to a year for getting the GC after being current, you are looking at 12+ years.
I have to apply for my sis too, but with this kind of delay not sure if i would.
Also US Govt does not care about this caregory so it will get worse instead of getting better with every year. 5 years back it was like 8 years if remember correctly.
Hope it helps.
Disclaimer: This is not professional advise.
