http://www.vgchartz.com/
NDS：50.28
PSP：23.37

Where Do Our Numbers Come From?（VGCHARTZ）

Unlike many other websites (which use manufacturer shipment figures and reports to estimate current console sales), VG Chartz collects data directly from retailers all over the world. Retailer sample sizes are small compared to professional tracking services, but are large enough to provide very accurate projections of the latest console sell through figures worldwide. We are the only provider anywhere in the world of weekly American sales charts and are expanding our data collection and coverage all the time. To find out more, visit our about us and methodology pages.