I don't have the specific numbers for you, but I can offer some logic to back it up.
Criminologists agree that the number one predictor for future criminal behavior is - you guessed it - past criminal behavior. Race, age, income level, and education are all less effective at predicting future criminal activity.
Needless to say, if you have gather together group of adults, all without a criminal history, you have a group of people who are very unlikely to commit a crime in the future.
(Legal) gun owner comprise just such a group. You can't own a gun if you have a previous felony conviction, and you can't own a gun if you are a minor. It's not surprising that gun owners seldom commit crimes later in life, since all of them managed to make it to adulthood without a serious criminal record.