gunug, you & I make the stat true. You are under 55 & I'm (way) over 55.
The older person usage could also be related to the fact that in the 80s when the Mac came out, it was easier to use than a PC that had DOS commands that you had to remember. Persons that were in their mid-30s when the Mac came out, are now over 55. Plus, generally, as a person ages, they are less likely to change brands, customs, etc because they are "comfortable" with what they are using/doing.
Plus, as most of TSers know, we are "smarter" than the average computer user. That's why we have a Mac.