U.S. Internet users in January watched less online video than the previous month. YouTube continued to account for the largest amount of video watched on the Web, a market research firm said Friday.

A total of 9.8 billion videos were viewed online in the U.S. in January, down slightly from the 10.1 billion viewed during a record-breaking December, ComScore said. YouTube, which is owned by Google, accounted for one out of every three videos watched in January.

U.S. visitors watched 3.4 billion videos total on Google sites, an increase of 1.7 share points from December, ComScore said. YouTube accounts for more than 96% of videos viewed on Google sites.

Coming in a distant second was Fox Interactive Media, which is owned by News Corp. and includes the Web's most popular social network, MySpace. Fox had a 6% share of videos watched, followed by Yahoo, with 3.2%, and Microsoft sites, with 2%.

More than 139 million U.S. Internet users spent an average of 206 minutes per person watching online video in January. Google sites attracted the most viewers, 80 million; followed by Fox, 53.9 million; Yahoo, 36.3 million; and AOL, 21.9 million.

ComScore's most recent report also found that three-quarters of the total U.S. Internet audience viewed online video, which lasted an average of 2.9 minutes. The average online video viewer consumed 70 videos.

Also, YouTube had 78.5 million video watches in January, while MySpace had 49.4 million. The average number of videos watched per visitor on each site was 41.4 and 10.8, respectively.