This is actually a point we're trying to make on NUFOSMATIC: that the volume of UFO sightings is proportional to population (and clear skies - just as soon as we can find a good, public clear sky database). UFO Sightings are not just reported by yocals out in the deep woods, but by people who see airplanes and helicopters and blimps all of the time and can't make what they see match what they know.