I haven't been keeping up with the numbers for a little while now, but looking at them now, it's quite telling, even if I've ignored the amount of time an OS has been around to gain traction.
Most notable that 8 and 8.1 *combined* has less than half market share of the remaining XP users, and XP is about half of Win7.
I've called 8.x "Vista v2.0", and going on market share, it seems I'm not too far off.