The United States is the most heavily armed countriy in the world. According to polling firm Gallup, 39 percent of American households owned at least one gun in 2016. Ownership has varied in the past ten years, but was centered around the 40 percent mark for households (not individuals).
As many households own multiple weapons or have multiple gun owners, others sources count almost 90 firearms per 100 people. Many guns are owned by men in the older age brackets, close to 50 percent are 45 years and older (the base here is the overall population).