It continues to be an uphill battle for Nintendo regarding the Wii U as the system's sales remain stagnant.
Nintendo announced that lifetime sales of the Wii U is at 6.17 million units. Even though the system has been out for roughly 17 months, the number of units sold have been very slow.
On the other side, Sony's PS4 sold 7 million units already and that was achieved in just five short months.
Nintendo is hoping the Wii U can sell a further 3.6 million consoles for its financial year ending March 31, 2015.