The NPD Group has released a set of charts highlighting sales in various video game categories over the last few years. Of particular interest is a graph representing online-capable sales between 2006 and 2010. The Xbox 360 leads in the category, with online-capable game sales consistently doubling that of PlayStation 3 since 2008. The Wii reached roughly half of the PS3's online-capable sales in 2008, though that number declined through 2010.

When it comes to points cards used to purchase games and downloadable content online, the Xbox 360 trounces the competition with sales growing steadily every year. Sales of Sony's PSN cards seem to be on the rise, however, while Wii Point card sales have remained relatively flat.

Head over to Gamasutra for more chart-related goodness, including snapshots of 3D game sales and motion control sales.