The cost of gun injuries is the focus of a new study from the University of Iowa's College of Public Health. The study found the cost of gun injuries is north of $600 million a year. The researchers looked at data from 2003 to 2013 and broke down the number of gun injuries by age. People ages 15-to-44 were the most susceptible to gun injuries. When statistics are broken down by race, the study says black people are injured most often.