Obama's inauguration most-watched since '81

Nearly 30% of households saw network coverage Tuesday

Barack Obama's inauguration was one for the TV ratings history books.

Nielsen Media Research said 37.8 million viewers watched Tuesday's coverage of Obama's inauguration -- the most in recent decades.

Obama's audience is bigger than any presidential inauguration in 28 years. It's 27% higher than Bill Clinton's audience in 1993 and 30% larger than George Bush's in 2001. Ronald Reagan's first inauguration in 1981 drew a larger tally, however, with 41.8 million.

Obama's total includes telecasts on 17 broadcast and cable networks and measures the number of viewers who watched from 10 a.m.-5 p.m. The swearing-in ceremony itself spiked viewership considerably just after noon. The ratings do not factor in online viewing, which was significant (viewers watching the inauguration broke streaming video traffic records for CNN.com, FoxNews.com and MSNBC.com).

Among broadcasters, NBC News topped competitors. From 11 a.m.-12:30 p.m., at the height of the ceremony and Obama's inaugural address, NBC led with 11.5 million, followed by ABC (11 million) and CBS (7.2 million). From 10 a.m.-5 p.m., NBC averaged 8.7 million, followed by ABC (8.4 million) and CBS (5.5 million).

CNN broke into the broadcast ranks, beating CBS and topping cable. CNN averaged 8.5 million viewers between noon and 12:30 p.m. That compares with 5.5 million for Fox News Channel, and 3.1 million for MSNBC.

The Raleigh-Durham market had the largest TV audience with more than 51% of households tuned in; Seattle-Tacoma had the lowest with 18.8%. Market-by-market info here.

Overseas, Barack Obama's inauguration was must-see TV for Europeans. Some 11 million Germans watched coverage on one of the half-dozen channels carrying the inauguration live. Things were similar in France, where half the evening's TV audience -- more than 7 million people -- was glued to the screen. In Britain, the BBC said 5.1 million viewers tuned in for the inauguration while 6.5 million watched the highlights on the BBC's 6 p.m. evening news.

Also: HBO got back some early numbers for its "We Are One: The Obama Inaugural Celebration at the Lincoln Memorial" concert. The premium cable network ran the special three times Sunday night and garnered a healthy 4.1 million viewers among its subscribers, with another 700,000 views on HBO.com. The network is still waiting for a total number that includes non-HBO subscribers (cable operators opened the network up to nonsubs for the event). Also, Disney Channel is touting 3.4 million viewers for Monday's "Kids' Inaugural: We Are the Future" concert.

Paul J. Gough, Rebecca Leffler, Scott Roxborough and Mimi Turner contributed to this report.