The largest market in the country, New York, has nearly one in five homes (17.5 percent) receiving HD channels. And most of the New Yorkers who have purchased the expensive HD-compatible sets ordered packages with the channels (18.1 percent have the sets, 17.5 percent have the service).

It's unclear whether the growing rollout of sets receiving HD channels will draw in more advertisers to shoot commercials in this format. Except for events like the Super Bowl, many have retreated due to higher costs, among other issues. Ads not shot in HD can potentially have a negative effect on HD channels, since they cannot always fill up the entire width of the screen, and the programming of picture and sound quality are different.

Interestingly, Los Angeles beats New York as the market with 20.4 percent (1.2 million) homes with HD channel sets, but only 965,000 homes have activated it, according to Media Post.