Fox averaged 1.96 million viewers in prime time, a fraction below the 1.97 million viewers it recorded for the week before Labor Day last year, the Nielsen company said. "MasterChef," with 4 million viewers, was its most-watched program of the week, Nielsen said.

The Fox News Channel cable network had more viewers last week than its broadcast sister, an unusual but not unprecedented development.

Because of barbecues, fireworks and other outdoor activities, the weeks around July 4th are often the least-watched time of the year in television. Networks usually plan accordingly, keeping most of its best material on the shelf. CBS also had its lowest week in the ratings in nearly four years, Nielsen said.