Information on the family category preference being processed and the priority date being handled at a particular service center may change over time.
Additionally, the speed at which backlogs are being reduced at different service centers can vary due to a multitude of factors, such as staffing levels, resources allocated, policy changes, and case complexity. there were no specific reports or rankings indicating which service center was reducing backlogs faster.
For the most up-to-date information on processing times, priority dates, and backlog reduction efforts at the Vermont Service Center or any other USCIS service centers, I recommend visiting the official U.S. Citizenship and Immigration Services (USCIS) website or contacting USCIS directly through their official channels.
You can find current processing times and other information related to USCIS services on their website: https://www.uscis.gov/