A disturbing statistic

I've had many non-pilot friends and co-workers ask, "Is flying a small plane
more or less dangerous than driving a car?", to which my response has always
been "It depends on who is piloting the plane." However, in order to get
a firmer answer from a statistical standpoint on this question, I decided
to do a little homework:

According to the DOT, the 2005 automobile fatality accident rate is:
1.47 fatalities per 100 million miles traveled
(see http://www-fars.nhtsa.dot.gov/)

According to the 2005 Nall Report, the general aviation fatality accident rate
is: 1.2 fatalities per 100,000 flight hours
(see http://www.aopa.org/asf/publications/nall.html)

In order to compare these two statistics, we obviously need to assume an
average velocity for either automobiles or GA aircraft. If we assume an
average GA aircraft velocity of 150 mph, then the aviation accident statistic
becomes 1.2 fatalities per 15 million miles.

Thus, based on the above, it appears that the GA fatality rate is somewhere
around 7 times that of automobiles. Now I realize that one could fudge the
average GA aircraft velocity velocity up or down, but I'm farily confident
that it's not above 200 mph, nor below 100 mph, which brakets the aviation
fatality rate between 5 and 10 times that of driving. A sobering thought...

Comments?

-- Dane