Violent Crimes Prevented:
Under president Obama, the CDC performed a study on the defensive use of firearms.
This study determined that firearms are used to prevent anywhere from 500,000 up to 3,000,000 violent crimes per year.
If we assume that the vast majority of these defensive uses of firearms were performed by concealed carry permit holders, we can divide the number of violent crimes prevented (up to 3,000,000/yr) by the total number of concealed carry permit holders (currently 17,251,354) to get the percentage of concealed carry permit holders that will end up preventing a violent crimes (17.4%).
This number 17.4% multiplied by the number of people that we have helped get their concealed carry permit, should be roughly equal to the number of violent crimes that we have helped prevent.
Please note, this is just an estimate. The actual number may be slightly less.