Over the last year, Facebook has been scrutinized for its potential role in helping promulgate fake news and hyper-partisan content. Like the stages of grief, first the company denied the problem and over the last few months has admitted it and then slowly announced it would implement ways to try and fix it. But just how big is this problem? According to a Medium post by the Boston Globe‘s director of audience and Nieman fellow, Matt Karolian, it was and remains a big one.

Karolian wanted to figure out how polarizing posts performed on the platform over the last year. To track this trend, he looked at data from some of the biggest right- and left-wing blogs and compared that to some of the largest mainstream media players. “Throughout 2017,” Karolian writes, “partisan pages enjoyed significantly higher Interaction Rates than mainstream pages.” Which is to say that posts from pages like Gateway Pundit, Breitbart, The Other 98%, and Occupy Democrats performed way better than those from CNN, NPR, the Washington Post, and the New York Times.

Karolian adds that left-wing pages performed two times better than their right-wing counterparts. (On that note, right-wing media actually had fewer average interactions than the mainstream outlets, but overall the hyper-partisan pages prevailed when put together.)

It’s true that the partisan content sharing was at its peak during the start of the year, which isn’t that surprising. It’s interesting to note, however, that these pages remained more popular than mainstream sources throughout the entire twelve months of 2017.

Mark Zuckerberg pledged to fix Facebook this year, and this data surely helps illustrate the problem. Currently, the platform is working to emphasize local news, as well as posts shared from individual people. It’s unclear what impact this will have on news polarization. Meanwhile, Facebook’s engagement rate has been dropping, likely due to changes to its algorithm.

We’ll have to see what impact these changes make. You can read Karolian’s analysis here.