I think the numbers are higher than this

Reuters article on how the Army is relaxing its tattoo rules:

"The Army cited a 2003 survey of 1,010 people conducted at the Scripps Survey Research Center at Ohio University that found that roughly 30 percent of U.S. adults under age 35 have tattoos, and that the U.S. post-baby boom generations are more than three times as likely as the baby boom generation to have tattoos."