According to the Health Department, there are now six suicides per 100,000 people in the city — nearly half the national average of 11 per 100,000. The Health Commissioner is chalking up the relatively low figure to the city’s crackdown on illegal handguns. (Mayor Bloomberg nods approvingly.) Guns were used in only 12 percent of the city’s 503 suicides in 2010, compared with 51 percent nationally. “New York City has the lowest rate of suicides by firearm than any other large U.S. city,” said Health Commissioner Dr. Thomas Farley.