Nearly one in every three Americans owns a gun, according to a recently published study in the journal Injury Prevention by researchers Bindu Kalesan, Marcos Villarreal, and Katherine Keyes of Columbia University, and Sandro Galea of Boston University. The researchers conducted the survey of 4,000 adults in an attempt to answer the question of how many Americans own a firearm — and why — amid a lack of overall data and statistics on gun ownership.