A study by Gary Kleck and Marc Gertz found that Americans use guns in perceived self-defense nearly 2.5 million times per year. This same study found that nearly 400,000 Americans believe gun ownership saved their lives. Of course, these Americans might be exaggerating the danger they faced, and they might be mistaken in believing that a gun was necessary to save their lives. However, suppose just 1 out of 10 of these Americans were correct. Under that assumption, the number of lives saved by private gun ownership each year exceeds the number of lives lost
http://econlog.econlib.org/archives/2012/11/brennans_libert.html#
