Humans have been tattooing their bodies for thousands of years — the 5,300-year-old corpse of a man found in the Alps near the Italian-Austrian border was covered in them. It's the earliest known evidence of an art becoming increasingly common and socially accepted. (Remember when tattoos were a sign of a troublemaker?) In fact, more than 4 in 10 people in the United States have at least one tattoo, according to data from Statista. Here's a closer look at some of the more unexpected and eye-opening facts and attitudes related to ink in America.