thx1139 on 16 July 2011
My calculation
Current Number Sold +/- June NPDVGCDiff - Number Shipped Last Qtr + amount I expect to be on hand.
Wii : 87.64 - .129 - 86.01 + .4 = 1.9
PS3: 51.31 + .033 - 50.03 + .7 = 2.01
360: 54.61 + .198 - 53.50 + .7 = 2.0
Its libraries that sell systems not a single game.