I said this in a thread one month before the launch
"4M 1st week worldwide (I expect 5m shipped games at launch), 6M 1st month, 10M before year ends. Probably between 15-20M lifetime."
http://gamrconnect.vgchartz.com/post.php?id=8868932
So i was very close in the end (like i usually am, despite some recent opinions on the contrary...XD). I was just too much in the launch, but i have clear number in my mind it would sell 10M by years end.