4 weeks USA: WiiU: 849,068
Wii: 864,647
PS3: 378,603
X360: 477,303
So WiiU did 98% Wii, 224% PS3 and 178% X360. Looks excellent.
3 weeks europe:
WiiU: 340,310
Wii: 618,450
PS3: 691,843
X360: 403,037
WiiU in europe did 55% Wii, 49% PS3 and 84% X360. Bad here.
2 weeks japan:
WiiU: 437,390
Wii: 460,235
PS3: 130,335
X360: 65,430
In japan we have 95% Wii, 335% PS3 and 668% X360. OK, that is XBOX 360. In Japan.
4 weeks worldwide:
Keep in mind, the consoles didn't launch worldwide at the same time, so this is pretty skewed. It should work for Wii though, it was also launched in a window of some weeks.
WiiU: 1,817,166
Wii: 2,071,242
PS3: 524,687
X360: 948,162
That are 88% Wii, 346% PS3, 192% X360. Pretty decent.