March 2018 is the 13th month that the Nintendo Switch has been available for. During the latest month the Wii has closed the gap with the Switch slightly. The Wii outsold the Switch by 632,258 units in the last month and by 884,581 units in the last 12 months. The Switch is currently ahead of the Wii by 915,599 units.
The Wii launched in November 2006, while the Nintendo Switch launched in March 2017. The Switch has sold 16.11 million units, while the Wii sold 15.19 million units during the same timeframe.