The only thing that would even remotely resemble a fair comparison would be NPD April results for 2005 or 2006, right before this current generation launched. If this is a cyclical business, and everyone agrees it is...then comparing it to previous years in the current cycle is totally irrelevant.
Platforms sell best in their second and third years, and then they start to decline...so four, five or six years in, it's all about discount bundles being picked up by late adopters.