kd, refer to this document which I got from one of the USCIS bulletins in Nov 2003..this should give you a better understanding..its not just my friends cases, i have looked into threads in NY,NJ too..their cases are getting approved in 2 months, which kind of validates what it says below.
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Determining the priotrity date: Under INA § 203(f), immigrant visas are available in the order in which the underlying visa
petition was filed. The “priority date” determines an alien’s “place in line.” For EB-1immigrants, the priority date is the date
the employer files the Form I-140 with USCIS. For EB-2 and EB-3 immigrants, the priority date is the date the employer
applies for the labor certification, if an individual labor certification is required. If an individual labor certification is not
required, the priority date is the date the employer files the Form I-140 with USCIS. If the alien is the beneficiary of more
than one Form I-140, the priority date for EACH Form I-140 is the priority date for the earliest Form I-140. For EB-4
Immigrants, Form I-360 is used instead of Form I-140. The priority date is the date of filing the Form I-360.
The Visa Office, U.S. Department of State, publishes for each month a Visa Bulletin, which specifies the priority date for each
immigrant visa classification. If an individual’s priority date is earlier than the priority date shown in the Visa Bulletin for the
particular immigrant visa classification, then an immigrant visa is available for the individual’s use. If the Visa Bulletin shows
the priority date as “C,” then an immigrant visa is available for all approved visa petition beneficiaries in that classification.
The current Visa Bulletin is available at
http://travel.state.gov, as are past editions of the Visa Bulletin.