I would still tend to agree with jenniferlyon that most skaters tend to come from the upper middle class. If not, their families would have to at least be comfortable. For example, the Kwan's mortgaged their home to help pay for Michelle's skating. To do that, they had to own a home to begin with, and not be renters. They also owned a restaurant IIRC. That may not be upper middle class but it's a long ways away from poor.
I would think that poor skaters like Tonya are few and far between.
What is upper middle class anyway, in terms of dollars?
The modest estimate that comes to mind for an elite skater is $50,000 a year. To put that in perspective, Patrick Chan once said his skating cost him $200,000 a year - granted, that figure probably included his mortgages.
So for parents to afford $50,000 per year and still support a family and at least a middle class lifestyle, which I'll guess would take $100,000 per year, they would probably need to be earning at least $150,000 per year - not a whole lot really for two working professional parents.