I think this is a more fair comparison (although it slightly gives an adv. to 07).
2007:
Week ending 17th + week ending 1st (dec)
Wii: 1141K
Ps3: 615K
X360: 581K
Total: 2337K
2008: Week ending 15th + 22nd
Wii : 1424K (+ 26.2%)
Ps3: 433K (-29%)
X360: 740K (+ 27,5%)
Total: 2597K (+ 11.1%)
As this gives a fair edge to 2007, I think we can say that overall, it is + 15-20%, + 30-35% for Wii, -20-25% for Ps3 and + 30-35% for X360.
Either way - decent increases.
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS