Interesting to see this data, but I've always been skeptical of VGChartz. They've been known to not be the most accurate source. They are a good for aggregating all the reliable data into one place. I know they use NPD, Media Create, etc.. to come up with worldwide estimates, but I've also seen instances where they claim to have the most recent and latest numbers but their sales are just based on algorithms and recent sales trends. I think they claim to have sales for consoles updated weekly or something, but there is no way that is even possible. Even Sony, MS, and Nintendo don't have that information which is why they rely on NPD numbers to make announcements to the public.
Regardless, appreciate the link. Glad to see Killzone doing pretty well. I always thought that was a series that deserved more recognition and that this would be a good time for it to shine since it was a launch title and one of the only next generation FPS games (there is CoD and Battlefield, but both of those have current generation counter parts, so they weren't built from the ground up for the PS4 of Xbone).