FORTUNE — Netflix NFLX is grabbing an increased share of North American Internet traffic during peak hours, according to a study released Wednesday.

Waterloo, Ontario-based Sandvine’s bi-annual traffic trends report shows Netflix users accounted for 34.2% of all downloaded web traffic during peak evening hours in North America so far this year, a share that grew from 31.2% during the second half of 2013. Sandvine notes that the increase is likely due to the expanded availability of Netflix’s “Super HD” content.

YouTube is a distant second to Netflix in terms of downloaded traffic, with a 13.2% share in North America, according to Sandvine. Fellow streaming video services Amazon Instant Video and Hulu both hold shares below 2% of all downloaded traffic.

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Sandvine says Netflix is also growing rapidly in the U.K. and Ireland, where the streaming service launched just two years ago. Netflix owns the second-largest share of downloaded web traffic during peak hours in these countries, 17.8%, trailing only YouTube’s 19.9%. But, Sandvine says Netflix’s share has expanded quickly and is expected to overtake YouTube “within the next year.”

The increase in traffic has led Netflix to cut deals with broadband providers Comcast and Verizon in recent months to ensure a more direct connection and increase the streaming speed for Netflix customers. Terms of the deals were not disclosed, but the arrangements fed into the debate over net neutrality and whether or not the government should allow broadband providers to charge certain companies extra for faster Internet service. (Federal Communications Chairman Tom Wheeler has drawn fire recently for his proposal to create “open Internet” rules.)

The report, which is based on data provided by Sandvine’s communications service provider clients, also tracks the data usage of people it calls “cord cutters” – or, those who eschew traditional cable subscriptions in favor of online entertainment. Sandvine says in North America those people account for 54% of all the downloaded web traffic each month. Cord cutters consume an average of 100 hours of downloaded video each month, and a total of 212 gigabytes of data.