This info is a bit out of date, but probably still close to the current situation; in fact, it’s probably gotten worse. From the American Academy of Pediatrics: Firearm-Related Injuries Affecting the Pediatric Population — Committee on Injury and Poison Prevention 105 (4): 888 — AAP Policy

In 1997, 32 436 firearm-related deaths (12.12/100 000) occurred in the United States, of which 4223 of the victims were children and adolescents younger than 20 years of age.1Handguns continue to account for the majority of deaths and injuries from firearms in the United States.2–6 Compared with the period from 1980 through 1985, death rates from firearms for children and adolescents increased by 31.8% during 1986 through 1992, primarily as a result of increases in the number of homicides.7 The data from 1993 through 1997 indicate a decline each year in the overall number of deaths and death rates from firearms. For all ages, the rate of firearm-related deaths fell in 1997 to 12.12 after peaking in 1993 at 15.36 per 100 000. In 1997, firearm-related deaths for adolescents 15 through 19 years of age decreased from 28.00 in 1994 to 18.84 in 1997 (Fig 1). This decrease establishes a downward trend after nearly 10 years of increase.

Nonetheless, by the year 2003, firearm-related deaths may become the leading cause of injury-related death.8 In fact, in 1996, in 5 states (Alaska, Louisiana, Maryland, Nevada, and Virginia) and the District of Columbia, firearm-related deaths already outnumbered the deaths related to motor vehicle crashes (A. Crosby, written communication, February 1999).

In 1997, firearm-related deaths accounted for 22.5% of all injury deaths in children and adolescents 1 through 19 years of age.1 Among adolescents 15 through 19 years of age, 32.2% of all injury deaths are firearm related (Table 1). Among black males 10 through 34 years of age, injuries from firearms are the leading cause of death.9 Most firearm-related deaths of children occur before their arrival at the hospital.