Wii U 10 million, Xbox One 15 million, or PS4 20 million which will come first?

[Farsala]

If price cut and more launches Xbox One should get 15m easy. Current situation with only 13 countries, then the Xbox One will be fighting the Wii U for the 10m mark. PS4 has most countries launched and Japan next year should get 5m quickly, but idk about 20m before either get 10m...