Such as the 1995 Kleck and Gertz study in the Journal of Criminal Law and Criminology referenced by the World Wide Web Gun Defense Clock.
The anti-gun lobby likes to trumpet the statistic that a criminal homicide is committed using a gun roughly every hour in the US. (Actually, they prefer to inflate the numbers by lumping homicides, suicides, police shootings, self-defense shootings and accidents together.) They don't like to talk about the other side of the coin, which is that someone uses a gun to defend themselves against a criminal attack roughly every 13 seconds; that one in three of those (about every 40 seconds) "probably" saves a life; and in half of those, roughly every 80 seconds, the defender believes someone would "almost certainly" have died. Less than one in ten of these (about every two and a quarter minutes) results in the attacker being wounded, even though more than half of the self-defense incidents involve two or more attackers, and a quarter involve three or more.
(In the majority of those defensive uses, no shots are fired; the attackers change their mind as soon as they see their intended victim is armed.)
The article from which the numbers are drawn is "Armed Resistance to Crime: The Prevalence and Nature of Self-Defense with a Gun," Gary Kleck and Marc Gertz, in The Journal of Criminal Law & Criminology, Northwestern University School of Law, Volume 86, Number 1, Fall, 1995.
