Well I don't have the exact figures but I'm guessing somewhere between 60-75% of the population only has SDTV's. I have like 60 relatives (a very small sample of the population yes, but a good representative sample since theres dozens of different income levels and types of jobs, family situations and lifestyles) but only me and 2 of my brothers have HDTV's. According to my calculations that's 5%! How's that for a statistic?
Sitting outside an electronics store is a poor way to do research, its not a true representation of the total population. That's like trying to do a survery of how much of the population likes jazz music, but only doing it at a jazz club.
To get a good representative sample you'd have to go to alot of stores on top of Best Buy: grocery stores, department stores, clothing stores, video stores, video game stores, computer stores, music stores, furniture stores, office supply stores, etc.