actually - you can read up on the npds methodology.
you clearly don't want to, which is why you haven't.
since you haven't, there's nothing to discuss here except your assumption that wal-mart and other stores experience significantly different games sales just because they sell more than games -- despite the fact the fact you have no reason to think so other than your own seat of the pants analysis.
the amazon top 20 is such a small segment and relative of such a small segment of time that only your lack of knowledge is displayed by comparing the two, even in jest
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