16. It would be hard to get much safer than CCW permit holders already are.
To take Ayoob's advanced handgun defense course you will be required to have a BACKGROUND check and a personal CHARACTER letter. If all CCW teachers required that for their courses our streets would be safer. No CCW class, no permit. Perhaps this is also an idea that could be used by gun dealers and sellers too.
Considering how infrequently CCW permit holders are currently involved in crime - any kind of crime - it seems unlikely that additional permit requirements would make much of a difference.