I think, sadly, it probably is relevant, because these sort of figures help athletics coaches and governing bodies work out whats going wrong.
My former athletics coach, who has coached an Olympic athlete, has written articles about how standards are declining because there just aren't as many active young children coming through as in the past. When he gets them at age 13/14, its just too late for them to catch up on the motor skills from leading active lifestyles that children used to have in the past. Note basic good motor skills, not even sport specific skills.
It does seem to be a fact that children from middle class, private school backgrounds tend to be more active. It also seems to be a fact that children with sporty parents tend to produce sporty children.
This is running, which is one of the cheapest sports to do, and which in the past, has had what I think you could describe as quite a working class image. Went back to a training session with my coach at the track recently and it was true, more than half the kids there were from local private schools.
Its also to do about the motivation and determination of the athletes involved. There are kids that travel an hour or more by bus to get to training. And then there are the ones that live next door and don't turn up because it rains. Subsidised busses are laid on for most competitions, but if the athletes can't be bothered getting out of their beds in the morning and would rather play on their playstations, theres not much you can do.
Reading on here, you can tell that theres quite a lot of posters who are completely unfamiliar with competitive sport, and consider it quite a negative thing.
MrsTerry cycling is considered anything but an expensive sport in France, Belgium, etc..