Wii's Best Selling Game is New Super Mario Bros.
Multiplayer Mario crosses Wii Fit, according to ASCII data.
In its weekly sales report this week, ASCII Media Works reported that New Super Mario Bros. Wii is now the Wii's top selling game.
According to ASCII, the multiplayer Mario title sold an additional 35,580 units this week, placing it in second place behind Pokemon Ranger: Path of Light. The game's total is now 3,495,000 units, placing it just ahead of the 3,474,000 units of the previous number one game, Wii Fit.
Media Create and Enterbrain are usually cited for sales data here, most notably in the weekly sales chart. ASCII publishes weekly data as well. It's usually posted through Dengeki series websites and magazines. Data from the three trackers usually differs slightly.
Given that Mario has remained in the top ten since its early December release, it was pretty much inevitable that it would overtake Wii Fit, whose sales have presumably slowed since the release of Wii Fit Plus. It may very well have already topped Wii Fit in Enterbrain and Media Create's databases but the feat was just never reported.