http://cube.ign.com/articles/463/463155p1.htmlNintendo GameCube sold 1.1 million consoles in December and it's total US sales are now up to 6.8 million.
"The last number I have is from September, which is about 10.5 million units."
+ 165,000 (September US sales)
+ 254,000 (October US sales)
+ 748,800 (November US sales)
+ 1,100,000 (December US sales)
+ 550,000 (my estimate of how many GameCubes have been sold in Japan since September)
=
13,317,800 Nintendo GameCube consoles sold worldwide. (not counting sales from Europe, Australia, and other regions that aren't the US or Japan - since September)
I would assume GameCube is around 14 million worldwide if you add the non-existant European numbers.