In contrast it appears that the Wii moved a little under 6 million units worldwide by the March following its launch. Somehow, I suspect that Nintendo is betting that the Wii U will be a significant success on the same level as the Wii U, a very high target indeed.
Of course, this is assuming drastically reduced Wii sales numbers of about 4-5 million this fiscal year, almost a 50% drop since last year. Actually, given the extreme end-of-life for the console and depressed NPD numbers, that doesn't sound that much of a stretch.