Here's the video of MS's CES conference so those who didn't watch it live can finally hear his exact words. Skip to 1:54:40

'We're the world sales leaders last year for consoles"

They didn't exactly make a huge announcement, he said it in a kind of matter-of-fact way. Why didn't they announce it at the beginning like the fact that it sold 66m, etc? Neither MS nor the media seem to be emphasising this much. Anyway here's the video:

http://www.microsoft.com/presspass/events/ces/liveevent.aspx

UPDATE: So... the recent NPD had the PS3 overtracked by 300,000 and the X360 by a whopping 1,200,000. How did the 360 outsell PS3 WW? That pretty much means that either Ballmer was wrong or that the VGC numbers are all over the place (entirely possible after what we've seen). Also, that would put 2.6m 360's on sheleves according to VGC with the US adjustment in mind.

Who would have thought. Xbox 360 severely undertracked. Just wow.

Congrats to MS. Guess their crazy advertising and really good Holiday deals did the job.

Really impressed, we are going to see so crazy numbers thursday. I think 3.5 million for the 360.

Honestly i doubt that it was under tracked that much, like i just can't believe it.

With 18m Kinect sold and such a YoY jump, I think it's clear that Kinect is selling X360s like a brand new consoles and stealing a lot of the Wii's audience.

Incredible. To think they will be announcing a new console in 6 months.

Really? Where is the source? I only see MS stated XO is the best selling console in USA. God, please give me the source. It makes me excited.

While it may very well be true (we all know vgchartz isn't 100% accurate), how exactly does Microsoft know they sold more units than Sony or Nintendo? With the way I have always understood numbers, console makers only know the amount of units they have shipped, not the amount stores have sold.

Could somebody explain this to me/

They know, they would never make such a claim without knowing. Let it go, they won.