From The Daily Bell:

In a research study sponsored by the United States Department of Justice, James Wright and Peter Rossi interviewed over 1,800 incarcerated felons, asking how they felt about civilians and gun ownership. Thirty-three percent of these criminals admitted to being scared off, shot at, wounded, or captured by a gun-owning victim. Sixty-nine percent of them knew at least one other criminal who had similar experiences. Nearly 80 percent of felons also claimed that they intentionally avoid victims and homes that they believe may be armed.