Almost 75 per cent of US internet users streamed video online in May, according to a report released Tuesday by ComScore, an internet measurement and analysis company.

The average US internet user watched more than 2.5 hours of video online during the month, according to the ComScore Video Metrix report.

Sites run by Google topped the monthly rankings with the most unique video streamers and the most video streamed, the report said. Google sites grabbed 21 per cent of all video streams in May, or 1.8 billion videos - 1.7 billion from Google subsidiary

Fox Interactive Media ranked second, with 680 million streams, or 8 per cent of the total, followed by Yahoo sites, with 387 million streams, or 4 per cent, and Viacom Digital, with 237 million streams, or 2 per cent. In all, Americans viewed more than 8.3 billion streaming videos online in May, ComScore said.

Google's streaming video audience totaled 64 million unique streamers, nearly half of the 132 million Americans who viewed online video streams in May, according to ComScore's research. Fox served 52 million unique streamers, with Yahoo pulling in 35 million, the report went on to note.

The average video stream was 2.5 minutes, with the average online video viewer consuming 653 video streams or more than two per day, ComScore said.