So, this is an interesting question for my Switch, because it's used by 3 different people. Personally, I play about 90% docked because I prefer to use the Pro Controller. But since the D-pad on that controller isn't great, I play certain games like Tetris 99 or NES games in portable. My daughter is almost 100% docked as she basically only plays Fortnite or BOTW on the TV. My son uses it 100% portable. He takes it to his room and plays there, and he logs the most hours on Switch out of the 3 of us.
So, in total it's about 50/50 I think.