Based on research, it looks like around 30% of Americans own a gun [1]. So you may just live in an area with a lot of gun owners. Also, not everyone owns a gun for the same reason. Some for protection, some for hunting, some for antiques, etc etc. I've owned my house for a few years and last year I found a couple of shotguns tucked away next to a bookcase in a closet. I eventually got rid of them, but for a few months I would have technically had to raise my hand for that question.

[1] http://www.pewsocialtrends.org/2017/06/22/the-demographics-o...