Teddy, thanks I actually didn't look at Trackitt yet. I've been looking at the pending I-485 inventory list released by USCIS on June 1, 2011.
http://www.uscis.gov/USCIS/Green%20C...une%202011.pdf
As you can see in the list, there is a significant number in 2006 (15,000 +) that have not been granted a visa number, yet DoS went ahead and advanced the date to March 2007. All of us know that USCIS doesn't work strictly on FIFO basis, they've approved applications randomly although within the confines of visa bulletin.
I guess, CO must be thinking what a jerk USCIS is, I better move the dates ahead otherwise these guys because of their random picking/approvals, will waste visas.
That theory above should lead CO to advance the dates much farther then the numerical analysis suggests...just a thought.
Maybe that's why they've stopped releasing demand data because they'll look stupid. The demand data will dictate that there is demand from prior year, but yet DoS advanced the dates (because of inefficiency of USCIS).