According to an announcement sent by Nintendo, Mario Kart 8 sold 1.2 million copies in its first three days on the market.
The announcement does not specify whether it refers to units delivered to retailers or purchased directly by consumers. “So many positive reviews of Mario Kart 8 reinforce the gameplay possibilities that the Wii U naturally offers,” states Nintendo of Europe president Satoru Shibata. More news about Nintendo's future will be revealed at E3 2014.
Finally, the game was released on May 30th and is exclusive to the Wii U console.