So according to GAON, kpop industry sold around 55 millions albums in 2021 (latest update was november).
The december update isn't out yet, but since expectations go lower than 60 millions as the final number, it's safe to say the NCT-only sales were around 1/5 of the total percentage.
The whole group, counting Universe latest update, has sold above 10.9 million albums this year, so it's almost a FIFTH of the total (expected) kpop sales this year...
We aren't talking about SM only, this is the whole industry.... Wow