NBC's London Olympic coverage has topped Beijing for the fourth night in a row.

The Nielsen company estimated that Monday night's prime-time coverage was seen by 31.6 million viewers, up from the 30.2 million who watched the first Monday of competition in Beijing four years ago.

At least initially, it had appeared NBC had fallen short of Beijing. Nielsen's overnight measurement of the nation's largest cities showed NBC's ratings down 5 percent from the 2008 Games. But Nielsen's viewership estimate is the more definitive number, a measurement based on Nielsen meters all across the country.

Four years ago on the same night, NBC was able to run many events live, including a gold medal race by Michael Phelps. NBC's prime time this year was all tape-delayed material, with a disappointing showing by the U.S. men's gymnastics team.