(Bloomberg) -- Three crashes which have yet to be fullyexplained, involving the most modern airliners in the safest phaseof flight, made last year the deadliest for air travel in almost adecade.

The loss of two Malaysian Air Boeing Co. 777s, one thought tohave disappeared in the Indian Ocean, and flight MH17 presumed shotdown over Ukraine, plus last week’s unexplained AirAsia tragedy,killed 665 passengers, accounting for 75% of the annual toll of884, according to safety consultant Ascend Worldwide.

The run of mystery crashes, which began when Malaysian AirlineSystem Bhd. flight MH370 vanished on March 8 and ended with thedemise of AirAsia QZ8501 on a routine trip from Java to Singaporeon Dec. 28, meant 2014 was the most lethal year in civil aviationsince 2005, when 1,056 died, Ascend said. The number of fatalcrashes was unchanged, and the balance involved older turbopropsflying in emerging nations and conforming more closely to thetypical profile for accidents in recent years.