“Mario Kart 8 Deluxe” is the top-selling Nintendo game for the company’s hybrid Switch console, with more than 15 million copies sold as of Dec. 31, Nintendo announced as part of its earnings release Thursday.

“Super Mario Odyssey,” with 13.7 million copies sold, holds the number two spot and “Super Smash Bros. Ultimate,” which was released just last month, has already sold more than 12 million copies, making it the third most sold game developed by Nintendo for the Switch.

“Mario Kart 7” is the 3DS’ top-selling Nintendo game with 18.1 million copies sold, according to Thursday’s update.

Nintendo also announced Thursday that it was delaying the release of its smartphone version of the Mario Kart franchise to this summer. The game was delayed, according to the company, so it could improve the quality of the game and “expand the content offerings after launch.”

With a relatively sparse line-up of first-party titles announced by Nintendo for the Switch, a new Mario Kart game for the hybrid console would be a good way to invigorate sales of the platform. Nintendo has said in the past it uses its smartphone games to help, among other things, market titles for its own platforms.

“The Legend of Zelda: Breath of the Wild,” the two “Pokemon: Let’s Go” titles, “Splatoon 2,” “Super Mario Party,” “1-2 Switch,” “Mario Tennis Aces,” and “Kirby Star Allies” round-out Nintendo’s top ten list of first-party games for the Nintendo Switch.