U.S. airlines had their most fatal air crashes last year since 1968 but the government says the overall accident rate for commercial air carriers and commuters declined. In all, 278 people were killed in 11 crashes in 1989 involving scheduled and non-scheduled air carriers, down slightly from the 285 in 1988, the National Transportation Safety Board said Wednesday. The most deadly year of the decade was 1985 when 526 people were killed in seven fatal commercial aviation accidents. The least destructive year was 1980 when only one fatal accident took place, killing just one person. Also last year, 763 people died in accidents involving private or general aircraft, the safety board said, the lowest figure for that category since it began keeping statistics. There were 781 deaths involving general aviation accidents in 1988. The board said the fatal accident rate for general or private aviation continued ``an improving trend that lasted most of the decade.'' Despite the high number of airline accidents involving fatalities last year, the overall accident rate for commercial air carriers and commuters declined, the safety board said. There were 28 accidents involving U.S. scheduled and charter airlines last year, a decrease from the 32 accidents recorded in 1988. The 11 involving fatalities were the most since the 15 of 1968. The fatal accident rate was 0.144 for every 100,000 scheduled and charter departures, up from 0.026 in 1988. The major scheduled U.S. airlines had 24 accidents last year, down from 31 the previous year. Of those two dozen accidents, eight involved fatalities, the most since 1973. Accidents involving scheduled airlines took 131 lives last year, 111 of them when a United Airlines DC-10 crashed in Sioux City, Iowa on July 19. The safety board noted a passenger who died 31 days after the accident was not registered in its statistics. The scheduled-airline accident rate for each 100,000 departures was 0.328, down from 0.412 in 1988. The fatal accident rate rose from 0.027 to 0.109. Charter airlines experienced four accidents during the year, three of them involving fatalities. A total of 147 people died, all but three of them in the Feb. 8 crash of an Independent Air B-707. There were no fatal accidents involving chartered aircraft in 1988. Here are other aviation accident statistics for 1989: _Commuter flights: There were 18 accidents, one fewer then in 1988. Five fatal accidents, up from 2 in 1988, took 31 lives. That was 10 more than in 1988. The accident rate: 0.621 for each 100,000 departures compared to a rate of 0.654 in 1988. The fatal accident rate rose from 0.069 to 0.172. _Air taxis: Accidents rose from 98 in 1988 to 110. The number of fatal accidents declined from 27 to 23. But fatalities increased from 58 to 80. The accident rate rose from 3.45 to 3.83 for every 100,000 aircraft hours. But the fatal accident rate dropped from 0.95 to 0.80. _General aviation: The accident rate dropped for the seventh year in a row from 7.97 for each 100,000 aircraft hours in 1988 to 7.25. The last increase in the accident rate took place in 1982 when it was 10,06. The fatal accident rate declined to 1.40 for each 100,000 hours from 1.52 in 1988.