Hmmm, I wonder what their source is? That's pretty crazy and means they've already zoomed past Wii U in well under a year, which is nuts.
I suppose, if Nintendo did mention selling through over 10 million on Dec 10th, it's feasable they've sold 3-4 million more in the month since then worldwide, being the holiday season it's possible - and the 15 could be shipped as of January, meaning 1-2 still sitting on shelves which sort of makes sense.
"We hold these truths to be self-evident - all men and women created by the, go-you know.. you know the thing!" - Joe Biden