The following is a list from the Harvard School of Public Health. For explanations and sources, see the web page.

1-3. Guns are not used millions of times each year in self-defense.

4. Most purported self-defense gun uses are gun uses in escalating arguments and are both socially undesirable and illegal.

5. Firearms are used far more often to intimidate than in self-defense.

6. Guns in the home are used more often to intimidate intimates than to thwart crime.

7. Adolescents are far more likely to be threatened with a gun than to use one in self-defense.

8. Criminals who are shot are typically the victims of crime.

9-10. Few criminals are shot by decent law abiding citizens.

http://www.hsph.harvard.edu/hicrc/firearms-research/gun-threats-and-self-defense-gun-use-2/