WASHINGTON — Malicious acts surpassed accidents as the chief cause of airline deaths worldwide in 2015 for the second year in a row, according to an industry tally.

There were eight accidental crashes last year, accounting for 161 passenger and crew deaths — the fewest number of crashes and deaths since at least 1946, reflecting continued improvement in safety technology and aircraft design, according to Flightglobal, an aviation news and industry data company.

The 161 accidental deaths tally is far outpaced by the 374 killed when a Germanwings airliner was deliberately flown into a mountain in the French Alps last March and a Russian airliner packed with tourists exploded over Egypt in October.

In 2014, the toll from a Malaysia Airlines plane that disappeared and another that was shot down over Ukraine was 537 deaths, compared with 436 accidental deaths that year.

The tallies are for all types of flights, including cargo, positioning, training, and maintenance. There were just 98 paying passengers killed last year. It’s a vast improvement from the 790 passengers killed in 2007, and the annual average of 1,289 passengers killed in accidental crashes in the 1970s.

‘‘In recent years, airline safety has improved very considerably to the point where, typically, there are now very few fatal accidents and fatalities in a year,’’ said Paul Hayes, Flightglobal’s director of air safety and insurance. ‘‘However, flight security remains a concern.’’

The global fatal accident rate for all types of airline operations in 2015 was one per 5 million flights, the best ever. The previous best year was 2014, with a fatal accident rate of 1 per 2.5 million flights. Airline operations are now about four or five times safer than they were 20 years ago.

A big reason is better engineering. Today’s airliners are more highly automated, which has reduced many common pilot errors. They have better satellite-based navigation systems. They are made of stronger, lighter, and less corrosive materials. And they’re equipped with systems that have nearly eliminated mid-air collisions as well as pilots losing situational awareness and flying into a mountainside or the ground.

But more needs to be done about disturbed pilots and terrorism, experts said. The Germanwings case is perplexing, said John Cox, a consultant. The pilot concealed his problems even though airlines continually evaluate pilots, and pilots evaluate each other.

It’s not known what caused Malaysia Airlines Flight 370 to disappear; experts theorize that it was the result of deliberate acts, probably by a pilot.

The Islamic State claimed credit for blowing apart a MetroJet A320 over Egypt. Malaysia Airlines Flight 17 was shot down by a Russian missile fired from rebel-held territory in Ukraine, Dutch officials say.