Linkzmax on 23 December 2008
NPD also tracks sold to consumers. For "sold to retailer" numbers we have to wait for the quaterly statements form the big 3.
As was mentioned, that wiki is probably NPD US only while VGC charts all of the Americas.
Additionally, several weeks of data have come in for VGC, while we'll still have to wait until the second week of January for December numbers from NPD.
Lastly, neither NPD nor VGC(nor any other tracking firm) covers 100%, and so they're both estimates. Which means they're unlikely exact and don't have to be identical, but should both give an accurate count.
