NBC's Olympics End on a Ratings High -- London Games Called Most-Watched TV Event in U.S. History TVbytheNumbers

Sunday’s final night of NBC’s Olympics coverage from London was way up from Beijing four years ago, according to Nielsen overnights. reports that the network’s telecast of the closing ceremony scored a 9.1 average rating in the key 18-49 demo, up 32% over the Beijing closing ceremony.

Earlier in NBC’s Sunday schedule, the 90-minute Olympics retrospective “London Gold” delivered a 5.7 average in viewers 18-49.

CBS had an overrun of its PGA golf coverage, meaning its numbers will be adjusted more than usual. According to preliminary numbers, the network’s fresh installment of “Big Brother” pulled a 1.9 average in 18-49, down from last week’s 2.1.

ABC’s fresh episode of “Secret Millionaire” managed a 1.0 in viewers 18-49, an improvement from last week’s 0.8, while a two-hour “Extreme Makeover: Weight Loss Edition” settled for a 0.9, up from a 0.8 a week ago.

For Sunday prime time overall, NBC was well out front with a 7.8 average in 18-49, followed by Fox (1.3 average), CBS (1.2) and ABC (0.9). Total viewers saw NBC on top with an average of 27.0 million, followed by CBS with 4.7 million, ABC with 3.5 million and Fox with 2.8 million.

NBC summed up its two weeks of Olympics coverage with an announcement declaring the London Games the most-watched television event in U.S. history.

More than 219 million people watched the 2012 Games, the network said, up from the 215 million who watched the 2008 Beijing Olympics. Additionally, the network said it experienced a “halo effect,” with the Olympics raising viewership across NBCUniversal platforms.

Prime-time Olympics coverage averaged 31.1 million viewers, the network said, making London the most-watched non-U.S. Summer Games in 36 years. The figure topped Beijing by 12% and Athens, in 2004, by 26%.

NBCU said it presented the London Games -- NBC’s 13th Olympics -- with an unprecedented 5,535 hours of coverage across NBC, NBC Sports Network, MSNBC, CNBC, Bravo, Telemundo,, two specialty channels and the first-ever 3D platform.