Assassination and dancing has proven to be a lucrative mix, as Just Dance 2 and 3 and Assassin's Creed: Revelations helped Ubisoft to lead this year's best seller's list with three entries. That's according to the NPD Group, which also estimates the video game industry's profits, comprising "new physical video and PC games, used games, game rentals, subscriptions, digital full-game downloads, social network games, downloadable content, and mobile games," reached sales of somewhere between $16.3 and $16.6 billion in 2011.

Activision's Call of Duty: Modern Warfare 3 took top honors (it's kind of a big deal), while Just Dance 3 and Skyrim occupied the second and third spots, respectively. NPD also says that, despite sales growth in the digital sector yet again, physical copies offered at retail outlets still accounted for the majority of sales coming in at $9.3 billion, "an 8 percent decline over the $10.1 billion in 2010."

That decline was "partially" offset by increases in digital, mobile, and used game sales, which NPD expects to be a focus moving into 2012. "Our overall estimate of the market continues to point toward the increased imperative for deeper visibility into digital distribution than is available today, not only in the U.S. but globally," said NPD prez David McQuillan. Our waning shelf space agrees.