Although no one is quite sure how many digital homes are actually watching HD content, more than half of American households now have at least one DTV set, says the Consumer Electronics Association, with about 80 percent of those digital sets capable of 1080p, 1080i or 720p. According to new CEA sales projections, manufacturers will post slightly more than 10 percent in revenue growth ($25 billion-plus), from DTV sales in 2007.

“Consumers are adding DTV to their homes at a record pace,” CEA President and CEO Gary Shapiro said on the eve of the trade group’s annual show (officially known as the “2008 International CES”) to be held Jan. 7-10 in Las Vegas.

Shapiro sees surpassing the 50-percent mark as “a critical threshold” for DTV in America and predicts that 2008 will be another banner year for HD, with CEA estimating nearly 32 million units forecast to ship to retailer. Right now, CEA figures put the estimated total number of HD sets sold in the last several years at 60.6 million. (Its numbers are based on product shipments, and it’s counting all DTV sets ever sold, regardless of how long ago.) Shapiro recently expanded on CEA’s DTV projections in a Q&A with HD Notebook.

For 2008, CEA is estimating 13 percent revenue, and 17 percent unit sales growth, for digital television.