Homicide Trends in the United States, 1980-2008
http://bjs.ojp.usdoj.gov/content/pub/pdf/htus8008.pdf
Details of homicide trends by age, sex, race, the relationship of victim and offender, law enforcement officers killed, weapon used, trends by city size and more. The homicide rate has declined sharply from 9.3 homicides per 100,000 people in 1992 to 4.8 per 100,000 in 2010. From the Bureau of Justice Statistics