In a statement released this evening, NPD analyst Anita Frazier says that in that short time, Black Ops has already surpassed Wii Play as the best-selling game in history. Like, ever. Activision hasn't released specific US life-to-date sales numbers, but it sold 5.6 million copies in the UK and US on day one. And as of October, Nintendo claimed sales of around 13 million Wii Plays.
So, more than that.