It's worth noting that the Nelson group recently reported it was wrong with its 27+ demographic. The Xbox 360 had the most usage, and the PS3 had the least usage. This reflects the other demographic too.
So for all three demographics usage looks like this:
Xbox 360: most (by far)
Wii: second
PS3: least (by far)
can the OP please update his post with this information?
For me:
Wii: 90%
Xbox 360: 10%