67 per cent of the world's 6.17 million Wii U owners also bought New Super Mario Bros. U.
The impressive attach rate was revealed in Nintendo's latest Wii U sales data, which stated that the side-scrolling launch title has reached 4.16 million sales worldwide.
Wii U's other biggest sellers are Nintendo Land at 3.09 million (50 per cent attach rate), Super Mario 3D World at 2.17 million (35 per cent attach rate) and New Super Luigi U at 1.76 million (28 per cent attach rate).
Further down the list, Wii Party U has sold 1.35 million copies and The Legend of Zelda: The Wind Waker HD 1.22 million copies.
Lifetime Wii U software sales total 32.28 million units, with 18.86 million units sold in the most recent financial year.
On 3DS, Pokémon X & Y is the handheld's best selling first-party title with 12.26 million sales, ahead of Mario Kart 7 (9.62 million) and Super Mario 3D Land (9.27 million).
During the fiscal year ended March 31 2014, Luigi's Mansion: Dark Moon hit 3.98 million sales and The Legend of Zelda: A Link Between Worlds reached 2.51 million sales.