Based on the Centers for Disease Control and Prevention’s (CDC) new HIV surveillance methods, the agency says that the number of new infections in New York City is triple the national rate, The New York Times reports. The city’s HIV incidence is 72 new infections for every 100,000 people compared with 23 per 100,000 nationally.

According to the article, 4,762 New Yorkers became HIV positive in 2006. Nearly two-thirds of those newly infected were between ages 30 and 50.

The CDC’s new data—released Wednesday by the city’s Department of Mental Health and Hygiene—revealed that sex between men accounted for half of New York City’s new HIV infections while 22 percent were attributed to high-risk heterosexual sex. Intravenous drug use was linked to 8 percent of new HIV cases, and 18 percent were from unknown or uncertain causes.