NBC Universal announced it has sold 90 percent of its Olympics ad list, after saying that it was striving to set a record of more than US$1 billion in ad sales, according to the Hollywood Reporter.

Even though there was speculation about declining ad revenues, NBC said advertising has recently increased, thanks to the networks reporting on the Olympic tryouts during primetime on weekends.

NBC mentioned last month that protests wouldn't have an impact on U.S. viewership during the games.

NBC's expenditure on the diffusion of the Olympics adds up to nearly $900 million. The network is trying to include 3,600 hours of coverage on its cable channels, NBC and Telemundo, as well as on the Web and VOD, according to the Hollywood Reporter.