Election night TV audience down from 2008: Nielsen data

LOS ANGELES (Reuters) - Tuesday's presidential election may have been too close to call for weeks, but it didn't pull in as many TV viewers as four years ago.

More than 66.8 million Americans watched coverage of the 2012 elections during prime time on Tuesday, according to final Nielsen data on Wednesday. That's down from the 71.5 million who tuned in to see the United States elect Barack Obama as its first African-American president in November 2008.

Nielsen said 13 cable and broadcast television networks aired live coverage of the election results, which saw Obama defeat Republican challenger Mitt Romney. Americans aged 55 and older made up the biggest audience, according to the ratings data.

The viewers for election night were also slightly down on the 67.2 million people who watched October's first presidential debate between Romney and Obama.

But activity on social media soared to a record level. More than 31 million, election-related tweets were sent on Tuesday night - including a couple from Obama proclaiming his victory - making the night "the most Tweeted about event in U.S. political history," according to Twitter.

(Reporting By Jill Serjeant; Editing by Paul Simao)