The online video ranking is rising month after month in the U.S., with YouTube surging ahead as the top online video content provider in June, according to ComScore.

The figures suggest 178 million Americans watched video content online in June with an average of 16.8 hours per viewer.

U.S has crossed the 6 billion mark by tuning in 6.2 billion videos during the month.

Google’s revenue largely driven by video viewing at YouTube.com with almost 150 million unique visitors and over 2.3 billion viewing sessions for the month.

comscore.com:Online

comscore.com:Online vieo proertise ranked by unique viewers in June 2011

Coming in a distance second was Vevo, with 63 million unique viewers and almost 400 million viewing sessions for the month. Yahoo ranked the third with 52.7 million viewers followed by Microsoft, Viacom, Facebook and AOL.

Hulu was in a distant ninth place with only 26.7 million unique viewers and some 157 million sessions, but it was second only to YouTube in one key metric: minutes per viewer. Google sites manages 324.1 minutes per while Hulu say 184.8 minutes per viewer Vevo same in third, with 112 minutes per viewer.

Hulu has also generated the highest number of video add impressions at more than 1.0 billion.

However, the Comscore figures leave out commercial video streaming services like Netflix, so for many U.S internet users, the total number of video streams and time spent watching them would be higher.