The year of 2015 has been "an extraordinarily safe year" for airline business with less air accidents and fatalities, said the International Air Transport Association (IATA) on Monday, one day before the Singapore Airshow.

There have been 68 accidents last year, less than 77 in 2014, among which four were fatal, also well below the number of 12 a year earlier, according to IATA's latest annual report on aviation safety.

"In terms of the number of fatal accidents, it was an extraordinarily safe year," said Tony Tyler, IATA's director general and chief executive officer.

136 people were killed, exclude the Germanwings and Metrojet incidents, said IATA, as the two incidents have been labelled as deliberate acts of unlawful interference. If include the above, the total fatalities will go up to 510.

The number of people killed were below 2014's 641 and also the five-year average of 504, IATA said, adding that the 2015 global jet accident rate, measured in hull losses per 1 million flights, was 0.32, slightly higher than the 0.27 in 2014 but below the average 0.46 in the previous five years.