Alright to comment on something ioi said, in holidays sales aren't more front loaded and sell better over that timespan. This is absolutely true and not hard to understand why. Take a game that releases in June and a game that releases in December. Let's say both open to 200,000. In June, the number of people buying a new console or just in a store buying video games is going to be exponentially less than that of someone in December. We call this increase holiday boosts or our general holiday increases. Thus meaning generally they might open to similar sales but because of normal holiday boosts the game released in December will sell more in the subsequent weeks then the game released in June. However, usually because of this and competition, it won't open to such high numbers either but worked for the sake of the example.
OT: as for the sales they are simply incredible. It does seem by the end of the year the game will have at least crossed 2 million. Compare this game and Wii Fit Plus to Nintendo's last holiday season offerings in Japan and you can see how this is a much better predicament for them.