The Nielsen study, conducted between April 2007 and February 2008, lumps all that data into one pool, so it's not hard to see where some issues might lie. It would certainly be interesting to see monthly breakdowns and observe if the Wii and PS3 received noticeable usage increases once high-profile games started showing up during Holiday '07. We also wonder what effect usage of console Blu-ray or DVD functionality had on the data. But what we're actually most curious about, is where the PS2 would be had it been incorporated into the data?
Update: Nielsen amended its 27+ data, apparently the Xbox 360 and PS3 info was accidentally reversed for the demographic; fixed image to match.
Source: How much use does Wii get?
[Via GameDaily, Thanks Master X]