The crash of Germanwings Flight 9525 in the French Alps today, which most likely resulted in the death of all 150 people on board, will undoubtedly lead to a re-examination of flight safety statistics.

What we’ll find is that although the number of crashes is steadily declining, the number of casualties per accident is on the rise.

According to the Aviation Safety Network, which collects data on fatal crashes of airliners (planes carrying more than 14 passengers), there were only 20 such events last year, making it the safest year to fly since 1942, when ASN’s dataset starts:

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Source: Aviation Safety Network

These data don’t include Malaysia Airlines Flight 17, which was shot down over eastern Ukraine: The 298 victims are regarded as casualties of war.

We are flying much more.  Ten years ago, U.S. airlines recorded 61 billion available seat miles — aircraft seats flown one mile — per quarter, according to data compiled by Bloomberg. Now, that number is up to 230 billion. Considering this increase in traffic, the shrinking number of fatal crash is especially impressive. The airline industry is doing a great job improving its safety. So why don’t we feel safer?

The simplest answer would be to blame media attention, which can affect perceptions of risk. The 20 fatal accidents recorded by ASN last year included the crashes of an Air Asia Flight over Indonesia, with 162 casualties, and an Air Algerie flight over Mali, with 116 victims, as well as the disappearance of another Malaysia Airlines flight that carried 239 people. Big accidents such as these naturally attracted a lot of coverage.

Measured by number of deaths per crash, last year ranks second only to 1985, when the worst crash in airline in history killed 520 people in the mountains of Japan, according to ASN. In fact, there is a general upward trend in this metric, though it is not particularly pronounced:

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Source: Aviation Safety Network

That probably shouldn’t be surprising. The global airline industry is gradually switching to bigger aircraft, which allow carriers to meet growing demand more efficiently, and reduce fuel consumption and cost per seat. There’s also a limit to the number of flights each airport can handle. Big planes are the industry’s future, Airbus said in its 2013-2032 market forecast.

By today’s standards, the single-aisle Germanwings Airbus A320 that crashed today was small, with just 150 seats. The trend, however, is for airlines to use bigger-capacity planes on relatively short routes, too.

This means that, even as air travel is generally getting much safer — the odds of dying on a major airline flight are one in 4.7 million — when something does go wrong, more people are likely to die. And things can always go wrong. The A320 is one of the safest commercial aircraft around, with only 0.08 fatal crashes per 1 million flights. The Germanwings craft went down in fine weather, during what is considered the safest flight phase — when it was at cruising altitude.

A few years from now, the same kind of flight will probably have more people on board.

This article was written by Leonid Bershidsky from Bloomberg and was legally licensed through the NewsCred publisher network.

Photo Credit: A Germanwings Airbus in Cologne, Germany. Dirk Vorderstraße / Flickr