According to Nance's recent book, The Terrorists of Iraq, that aggregated Sunni force -- the non-AQI insurgency -- constitutes almost all of the insurgency, with AQI possessing an estimated order of battle at about 1300 fighters and supporters, compared to 103,000 for the ex-Baathists and Iraqi jihadis. It should be said that Nance's book was published in May, just as the "Anbar Awakening" was taking shape, but the disparity between the Sunni insurgency and AQI he presents is large enough to make his estimate enduringly useful.
So what's up with playing down the Sunni insurgency? "This may be an information operation to make everyone in the Sunni insurgency be disgraced by being called AQI," Nance speculates. "However, I know Petraeus is fighting what he called 'from the middle to the extremes' and views the AQI and Mahdi militia as priority number one. He probably feels he can take the punches of the Sunni insurgents to the point where they are a continuing mission, just not mission number one." Perhaps more cynically, Nance adds, "He was fudging it but not actually making them disappear. He knows what Bush wants to hear."