(Reuters) - The U.S. television audience for Sunday's Super Bowl championship game of the National Football League on Comcast Corp's NBC dropped nearly 3 percent from last year, preliminary data by the Nielsen ratings agency showed on Monday.


About 47.4 percent of households in 56 major markets tuned in to watch the underdog Philadelphia Eagles defeat the New England Patriots, the early Nielsen data released by NBC showed, down from 48.8 percent a year earlier.


Updated ratings, including a total audience number, will be released later on Monday.


The Super Bowl traditionally ranks as the year’s most-watched event on U.S. television. Last year's game, broadcast by Twenty-First Century Fox Inc and which included a thrilling overtime finish, drew 111.3 million viewers.


Television ratings are being closely watched after the audience for National Football League games dropped almost 10 percent during the regular season.


(Reporting by Lisa RichwineEditing by Chizu Nomiyama)