Hours flown is rather misleading. I suggest the number of take-offs and landings ought to be considered. There could be several of these in the space of one flying hour. Very few of these would be at airfields with all the safety trimmings in place. Most of these (I'm thinking of my own experiences in Ulster) would have been in fairly confined spaces with no safety aids and as mentioned above in every type of weather, day or night. Not swinging the lamp, just giving an opinion.