Oyvoyvoyv on 15 May 2008
http://vgchartz.com/hwlaunch.php?cons1=XB®1=All&cons2=XB®2=All&cons3=X360®3=All&weeks=160
This one says 14.6M XB and about 19M X360 at the same time into life. Neither had staggered launches, so should be OK. That's 23% if I'm not mistaken, so these numbers are fairly close to ours.
Having said that, you can see that lately, the 360 has been going faster than the XB (for the first 75weeks they were virtually tied)
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS
