SAN FRANCISCO (MarketWatch) — A new research study released Wednesday shows that Netflix is becoming responsible for even more of the total traffic streamed over the Internet -- something that should come as no surprise to anyone who has ever used Netflix.

The report, from Waterloo, Ontario-based Sandvine Corp., said Netflix NFLX, -0.05% was responsible for 34% of Internet traffic downloaded during the peak evening hours in North America so far this year. That figure is up from 32% in the second half of 2013.

Netflix has seen its share of bandwidth usage increase as it has added more customers in the U.S. and abroad. At the end of its first quarter, Netflix reported 48.4 million video streaming customers, with 35.7 million of those in the U.S. The company is responsible for so much Internet video traffic that it felt it necessary to do a deal with cable giant Comcast Corp. to ensure its traffic gets routed directly onto Comcast’s CMCSA, -0.70% network.

“In North America, the dominance of real-time entertainment is due in large part to the continued market leadership of Netflix, which saw growth thanks to the continued rollout of high bitrate Super HD content,” Sandvine said in its report. “In the United Kingdom and Ireland, Netflix has also established itself as the second largest source of network traffic during peak evening hours.”

Google Inc.’s GOOG, -2.37% YouTube was still the second-heaviest source of traffic during peak hours, with 13% of total usage, but its numbers were down from 19% just half a year ago.

The figures on Internet traffic usage are likely to add fuel to the debate over Net Neutrality, which is the principle that all Internet traffic should be treated equally in spite of who is providing the traffic and the size of the data being streamed. Many broadband providers such as cable companies have argued that they could be able to give preferential treatment to specific Web sites based on the amount of data they are sending over the providers networks.

Federal Communications Commission chairman Tom Wheeler has proposed what he calls “open Internet” rules in which broadband providers can’t block or slow down access to high-traffic sites and content providers, but which would let those ISPs make deals with content providers to get preferred access to particular networks.

That was the type of deal Netflix reached with Comcast in February. When Netflix reported its first-quarter results in April, Chief Executive Reed Hastings said, “We felt we had no choice” about paying Comcast for faster service.

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