This report "[p]resents counts of full-time employees in general-purpose law enforcement agencies for 2016, with comparisons to prior years. General-purpose law enforcement agencies include municipal, county, and regional police departments; most sheriffs' offices; and primary state and highway patrol agencies. Results are shown by type of law enforcement agency and by sworn status. Rates of full-time sworn officers per 1,000 U.S. residents are also presented."
United States. Bureau of Justice Statistics: https://www.bjs.gov/