Tattoos and ear/body piercings are very popular, especially among those aged 18 to 22. Between 73 and 83 percent of women in the U.S. have had their ears pierced. An American university survey in 2001 found that 51 percent of students had piercings and 23 percent had tattoos. U.S. studies show that the number of women with tattoos quadrupled between 1960 and 1980. Tattooing procedures involve piercing the skin or mucous membrane with a needle or other sharp instrument. Unless the needles are new, sterilized for each treatment and properly handled by the practitioner, instruments can be contaminated with the infected blood or bodily fluids of another person. It is possible to transmit viral infections such as hepatitis B, hepatitis C, HIV/AIDS and herpes through tattooing and piercing, as well as bacterial skin infections such as Streptococcus and Staphylococcus.