Michael Phelps set one last record at the Olympics Saturday, and in the process he almost lived up to the lofty standards of Richard Mulligan.

Phelps won his eighth gold medal, a record for a single Olympics, as part of the U.S. 4x100-meter medley relay team Saturday night. His performance, and the run-up to it, helped NBC average 31.1 million viewers for the night.

That's the biggest audience for a Saturday-night program on the network since February 1990, when -- believe it or not -- an episode of "Empty Nest," which starred Mulligan, drew 31.4 million viewers. This was back in the days when cable was not yet everywhere and networks still programmed strong shows on Saturday nights.

Saturday's audience peaked at 11 p.m., when close to 40 million people tuned in to watch Phelps cap off his remarkable run with the seventh world record in his eight events, with help from relay teammates Aaron Piersol, Brendan Hansen and Jason Lezak.

NBC says that through the first nine days from Beijing, the Olympics have "reached" 191 million people on TV across all its networks, meaning that many people have tuned in to a least a few minutes of coverage. The broadcast network's prime-time average is 30.1 million viewers, a 15-percent jump from the 2004 Olympics in Athens (26.2 million).

Track and field, individual events in gymnastics and the medal rounds in a number of team sports will dominate coverage in the final week of the Games.