A new Justice Department study looking at violent crimes committed against “youth”—defined as Americans from 12 to 17 years of age—discovered that the rate of “serious violent crime” committed against youth by a perpetrator using a firearm dropped 95 percent from 1994 to 2010.

The study—“Violent Crime Against Youth, 1994-2010”–also discovered that American youth who were victims of a serious violent crime in 2010 were six times more likely to have been attacked by a perpetrator wielding a knife than one wielding a gun.

The study, released Dec. 20, also discovered that an American youth was 3.8 times more likely to become the victim of a serious violent crime if he or she lived in a home where the householder was unmarried than if he or she lived with married parents. In 2010, 7.4 out of every 1,000 youth living with married ...