Police Commissioner Raymond Kelly says the murder rate in the Bronx and the rest of the city is on pace to be the lowest since the NYPD started keeping track.Kelly said records show New York City is averaging less than one murder a day, which is an all-time low. In the Bronx, 22 people have been killed so far in 2007. During the same period in 2006, the number was 28 people, a 21 percent decline.A Daily News report says the commissioner is crediting the decline to Operation Impact. The program floods high crime areas with rookie police officers. NYPD supervisors are also crediting the elimination of an overtime cap for officers. They say it has led to police officers being able to make more arrests.The NYPD began tracking the number of city murders in 1969.