(Bloomberg) — YouTube’s most popular and prolific channels racked up 14.2 billion views in one week early this year. Videos starring and aimed at kids got the biggest audiences.

The figures came from a Pew Research Center report released Thursday. Pew studied footage uploaded during the first week of January from 43,770 YouTube channels. English-language YouTube videos featuring children under 13 netted three times as many views as others, on average.

Videos that starred and attracted kids — measured, in the report, by the presence of nursery rhymes, singalongs, toys, and other traits — were also more popular.

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The study highlights a major challenge for the Google unit: Children are a huge part of YouTube’s audience, but the company’s official stance is that kids under 13 don’t watch without adult supervision.

YouTube has settled Federal Trade Commission allegations that the company violated rules barring the collection of children’s data and the targeting of ads to kids, Bloomberg News reported earlier this year. The terms of the settlement have not been disclosed.

Pew Research looked at YouTube’s main site, not YouTube Kids, an app designed for minors that has struggled to build a large audience. YouTube prohibits children under 13 from watching its main service without supervision, but cartoons and toy “unboxing” videos still proliferate. The company has said that parents or older kids may watch these videos.

“We can’t speak to Pew’s methodology or results. But generally on YouTube, the most popular video categories tend to be areas like comedy, music, sports and ‘how to,”’ a YouTube spokeswoman said. “And we have always been clear YouTube has never been for people under 13.”