Nintendo of America president Reggie Fils-Aime says that Mario Kart 8 caused a large fluctuation in Wii U sales when it launched in North America on May 30th. Reggie says Wii U sales quadrupled the week after the release of Nintendo’s latest entry in the Mario Kart series from the week previous. Hopefully we should get some hard figures in June’s NPD results which should be made available sometime in July.