Investigators still don't know what caused an Asiana Airlines flight to land short of the runway at San Francisco International Airport yesterday, leaving two dead and scores of passengers injured. But even in the wake of such a tragic event, it's perhaps comforting to remember that traveling by air is as safe as it's ever been. There had been no fatalities on U.S. commercial jetliners for four years before this incident, putting your risk of death at about one in 45 million flights. Here's a chart of accidents for commercial aviation, including privately chartered planes as well as the big airlines, since 1992:

U.S. Commercial Aviation accidents and fatalities
(Source: National Transportation Safety Board)

The story's also good when it comes to number of accidents for the amount of time spent in the air. Here's the number of accidents and fatalities per 100,000 flight hours:

Rate of Commercial Airline accidents
(Source: National Transportation Safety Board)

The number of accidents is also declining in the general aviation category, which covers all types of smaller private planes. This chart goes back to 1975:

U.S. General Aviation accidents
(Source: National Transportation Safety Board)

And the rate of accidents there is declining even more smoothly:

Why the decline? As the New York Times explained last year:

Planes and engines have become more reliable. Advanced navigation and warning technology has sharply reduced once-common accidents like midair collisions or crashes into mountains in poor visibility.

Regulators, pilots and airlines now share much more extensive information about flying hazards, with the goal of preventing accidents rather than just reacting to them. And when crashes do occur, passengers are now more likely to survive.

So not only do you have a vastly lower chance of dying on a plane than in a car or even on a train, you also have a vastly lower chance than you did 20 or even 10 years ago. As horrific as the headlines are, it's actually one of the safer ways to spend time.