rendo on 04 October 2007
NDP does what ioi does here at vgchartz, but on a grander scale. NDP accounts for I believe 60% of retail, and then extrapolates the data to come up with their ESTIMATES. ioi does the same, but he has I believe 5% of retail, which is a large enough sample to base his numbers off.
NDP doesn't include Wal-Mart as they won't give their info out, typical slouches. It's possible there's variances because of this, but I trust vgchartz to be as accurate as possible for a fan site. :D
