What percentage of your shots should 3pt shots

I had a discussion with a few friends, and we talked about, what percentage of a teams' shots should be 3pt shots. A friend of mine said 50%, I thought that was the dumbest statement I ever heard. He said that equals champoinship. The consensus of the group was between 15-20%, what does everybody else think?

Who do you want?

Quinten Daley's mock 1.0