Google accounts 6% of all Internet traffic globally, and is the largest source of internet traffic, according to Arbor Networks' 2009 Internet Observatory Report. The University of Michigan and Merit Network also contributed to study, which looked at 256 exabytes of Internet traffic over the two years. “Five years ago, Internet traffic was proportionally distributed among tens of thousands of networks. Two years ago, 15,000 networks accounted for about 50% of online traffic. Today, 100 networks out of over 35,000 contribute 60% of all online traffic. Fifty-two percent of online traffic is Web (HTTP) traffic, up from almost 42% in 2007. And somewhere between 25% and 40% of that Web traffic is video,” noted.