The practices of body art date back thousands of years, with some of the oldest evidence of tattooing dating back about 6,000 years. Body modification in ancient times differed depending on the society it was practiced in, but it is believed that it ranged from sacred and religious practices to marks of social status, such as a mark on a slave or prostitute. By the early 1800s, roughly 90% of sailors had tattoos, generally marking something from their travels. For much of the 19th century, tattoos were prominent among sailors, soldiers, and the criminal lower class. Tattooing was seen as "outward evidence of their criminality". To what extent have the demographics of those who get body art shifted, and is there a correlation between body art and deviant behavior?