You can read the complete article and analysis here:
Switch vs 3DS and Wii U – VGChartz Gap Charts – December 2019
Switch Vs. 3DS and Wii U Global:
Gap change in latest month: 1,324,863 - Switch
Gap change over last 12 months: 3,046,464 – Switch
Total Lead: 76,633 - Switch
Switch Total Sales: 49,808,000
3DS and Wii U Total Sales: 49,731,367
Nice, Switch breaks ahead, and with 3DS and Wii U being as front-loaded as they were, they'll be no going back now.
I didn't think there would be a direct this week, cos I'm a pessimistic dunce.