Many studies have been done of the tattooed population and society's view of tattoos. In June 2006, the Journal of the American Academy of Dermatology published the results of a telephone survey of 2004. It found that 36% of Americans ages 18–29, 24% of those 30–40, and 15% of those 41–51 had a tattoo. In September 2006, the Pew Research Center conducted a telephone survey that found that 36% of Americans ages 18–25, 40% of those 26–40 and 10% of those 41–64 had a tattoo. They concluded that Generation X and Generation Y express themselves through their appearance, and tattoos are the most popular form of self-expression. In January 2008, a survey conducted online by Harris Interactive estimated that 14% of all adults in the United States have a tattoo, slightly down from 2003, when 16% had a tattoo. Among age groups, 9% of those ages 18–24, 32% of those 25–29, 25% of those 30–39 and 12% of those 40–49 have tattoos, as do 8% of those 50–64. Men are slightly more likely to have a tattoo than women.
Some organizations have proposed rules banning sleeves among their members; the United States Marine Corps prohibited Marines from getting arm- or leg-sleeve tattoos after April 1, 2007. Those with sleeves already are protected under a grandfather clause. Nevertheless, tattoo sleeves have become so popular that several clothing companies have produced apparel that simulates the look of tattoo sleeves using transparent mesh fabric printed with tattoo designs.
The American Academy of Dermatology distinguishes five types of tattoos: traumatic tattoos, also called "natural tattoos", that result from injuries, especially asphalt from road injuries or pencil lead; amateur tattoos; professional tattoos, both via traditional methods and modern tattoo machines; cosmetic tattoos, also known as "permanent makeup"; and medical tattoos.