A nonprofit group in Washington says the number of police officers who have died in the line of duty is up 43 percent so far this year.

The National Law Enforcement Officers Memorial Fund released preliminary data Wednesday. It shows that 87 officers died in the line of duty between Jan. 1 and June 30. That's compared with 61 officers during the first six months of last year.

The deaths were spread across 36 states and Puerto Rico - with California, Texas and Florida showing the most fatalities. Other states included Virginia and Maryland, where a state trooper was fatally shot June 11.

Among the causes of death were traffic accidents and shootings. If the trend continues, 2010 could become one of the deadliest years for U.S. police agencies in two decades.