PS4: 80-90mil
XBO: 55-65mil
Wii U: 18-25mil
So about %70 of last gen's total sales at the most for the big 3, mostly thanks to Ninty's colossal failure.
I'm kinda surprised to see so many 30mil+ predictions for the Wii U. I don't see much hope of it reaching those numbers - not with the way the system has been performing so far.