December 2018 is the 22nd month that the Nintendo Switch has been available for. During the latest month the Switch has closed the gap by 3.89 million units. However, in the last 12 months the Wii has outsold the Switch by 3.71 million units. The Wii is currently ahead of the Switch by 1.82 million units.
The Wii launched in November 2006, while the Nintendo Switch launched in March 2017. The Switch has sold 29.64 million units, while the Wii sold 31.45 million units during the same timeframe.