Kris Broughton reconsiders it using stats from Brian Michael Jenkins' book Unconquerable Nation:
Psychologists have learned that we rank fatal events by roughly squaring the death toll per event. An automobile accident with one fatality is seen as one fatality. One hundred accidents with one fatality apiece are still seen as 100 deaths. But a single event with ten fatalities has the same psychological impact as 100 individual fatalities, and an event with 100 deaths has the impact of 10,000 deaths.
This is why we pay more attention to increasingly rare airline crashes, which usually involve many fatalities, than we do to the much larger national death toll from automobile accidents. The terrorist attack on 9/11, with nearly 3,000 dead, had the psychological impact of millions dying.
The Dish 