First,
You can get I-485 employement-base 庫存名額 from this webpage(untill august 25,2009)
http://www.uscis.gov/USCIS/New%20Structure/3rd%20Level%20(Left%20Nav%20Children)/Green%20Card%20-%203rd%20Level/Pending%20Form%20I485%20Reports.pdf
Second, for example, there is 3015 I485 cases of Chinese EB2 untill the end of sepetember. If only, you can get to know the timetable, hoever, please see the following 3, 4,5.
Third, Ouestion is whether it includes NIW-based EB2?
Forth, sombody donot submit I-485 application due to cut-off date of the current Visa number.
Fifth, We donot know how many EB1 visa number can be left for EB2 or EB3, or How many Eb2 visa number from other countriess can be used for our EB2 or EB3.
So we only can evaluate the time in year or several months and can not get the exact timetable.
Just share my thought, please discuss.