New York ? Whether it’s around the dinner table or just in front of the TV, U.S. families say they are spending less time together.

The decline in family time coincides with a rise in Internet use and the popularity of social networks, though a new study stopped just short of assigning blame.

The Annenberg Center for the Digital Future at the University of Southern California is reporting this week that 28 percent of Americans it interviewed last year said they have been spending less time with members of their households. That’s nearly triple the 11 percent who said that in 2006.

These people did not report spending less time with their friends, however.

Michael Gilbert, a senior fellow at the center, said people report spending less time with family members just as social networks like Facebook, Twitter and MySpace are booming, along with the importance people place on them.

Five-year-old Facebook’s active user base, for example, has surged to more than 200 million active users, up from 100 million last August.