(CNN) -- One week, three airline crashes.
In Ukraine, the shootdown of Malaysia Airlines Flight 17 on July 17 killed all 298 aboard. Wednesday's crash of TransAsia Airways Flight 222 killed 48 in Taiwan, and on Thursday, Air Algerie Flight 5017 crashed in Mali, leaving at least 116 dead.
Then there's the unexplained loss of Malaysia Airlines Flight 370, with 239 aboard, in March.
Different circumstances surround the crashes, but when more than 700 airline passengers and flight crew lose their lives in the span of 138 days, some travelers might be concerned about the global aviation safety net.
They may wonder if, statistically, the skies are getting more dangerous. They may ask themselves whether 2014 is trending toward one of the deadliest years in aviation history. Experts say no, don't be nervous.
The world has been enjoying the safest-ever overall period in aviation history, according to the aviation safety number crunchers. As shown in the chart above, the numbers of yearly aviation deaths and major plane crashes worldwide have been dropping for decades.
Last year, 265 people were killed in flight incidents -- the safest year in aviation since 1945.
This year, the worldwide number of aviation deaths has more than doubled, but it's still relatively low. There have been 761 deaths in 12 commercial aviation accidents in 2014, according to the Aviation Safety Network, one of several organizations that tracks these statistics. Its data — spanning 1946 to the present — include hijackings, sabotage and shootdowns.
With the exception of the 9/11 attacks, it's hard to know whether the loss of three airliners in seven days is unprecedented, said Rudy Quevedo, global program director of Washington's Flight Safety Foundation. Crunching those numbers would "take us some doing and would be very labor-intensive," he said. "It is a rare event."
The U.S. hasn't seen a large airliner crash with major loss of life since 2001, when American Airlines Flight 587 slammed into the Queens neighborhood of Belle Harbor, New York, killing 265.
More recently, 49 died in 2006 in the takeoff crash of a regional jet: Comair Flight 5191 in Lexington, Kentucky. In Buffalo, New York, 50 died in another regional plane crash, Colgan Air Flight 3407, in 2009.
Last year's crash landing in San Francisco of Asiana Airlines Flight 214 — a Boeing 777 — resulted in three deaths.