How many people?

How many people are stuck at that level? I don't know.

How many people must be stuck there to justify the use of punishment as deterrent? My gut feeling is that we are not punishing too much unless the good done (to society) by deterrence is outweighed by the evil done (to the 'criminal') by the punishment.

And also remember that we can use carrots as well as sticks. A smile and a "Thank you" provide a powerful carrot to many people. How many? Again, I don't know, but I suspect that it is only fair to add these carrot-loving pre-conventionalists in with the ones who respond only to sticks.