Great research and great thread! Well done! It's kinda sad to see such a great OP getting so little interest from a site which focuses on numbers and statistics.
Considering the huge successes of Wii and DS it's only natural the series would decline following the less than stellar successors to these platforms, but it's interesting to note that Mario is still more popular now with low selling 3DS and Wii U than it was in the 90's when Nintendo sold more HW. I'm guessing this is a result of a diversification of Mario with all them spinn off games and such.
I'm on Twitter @DanneSandin!
Furthermore, I think VGChartz should add a "Like"-button.







