The aligned sales 8th generation has been able to stay ahead of the aligned sales of the 7th generation when you use the Nintendo Switch, instead of the Wii U. In the last month the 7th generation has closed the gap by 1.28 million units. However, in the last 12 months the gap has grown in favor of the 8th generation its lead by 2.91 million units.
The 7th generation of consoles in its first 15 months sold 39.65 million units, while the 8th generation of consoles sold 47.25 million units. The 8th gen currently leads by 7.60 million units.
The 7th generation of consoles sold a combined 274.35 million units during their lifetime, while the 8th generation has sold 136.33 million units through May 2018.