NEW YORK (AP) — High-definition televisions have rapidly become the norm in U.S. homes.

The Nielsen company said Wednesday that more than three-quarters of American homes have a high-def TV. Nearly 40 percent have more than one of those sets. As technology goes, that's a rapid adoption. In 2007, only 11 percent of U.S. homes had a high-def TV.

Nielsen, the company that measures TV ratings, says there's more of a taste for high definition than a supply of programming.

In May, an estimated 61 percent of all prime-time viewing was done on a high-def set. Yet only about 29 percent of prime-time viewing on broadcast networks was in true high definition. It was even less for cable networks.

Sports and entertainment are most likely to be seen in high definition.