Fake news about Donald Trump and Hillary Clinton had a big impact on the 2016 election. How big? A new chart from BuzzFeed’s Craig Silverman gives some idea of just how much influence bogus news stories had in the final months of the campaign:

Silverman used a tool called BuzzSumo to find the highest-performing legitimate news articles — stories from sites like the New York Times and the Huffington Post — and then compared them with high-performing stories that peddled false claims like “Pope Francis shocks world, endorses Donald Trump for president” (he didn’t) and “FBI agent suspected in Hillary email leaks found dead in apartment in murder-suicide” (this didn’t happen).

Silverman then compared the Facebook engagement — the number of shares, reactions, and comments — for the top 20 legitimate news stories against the top 20 fake news stories for three three-month periods. As you can see, the legitimate news stories outperformed the fake ones in the early months of the 2016 election campaign. But in the last three months, fake news sources saw their engagement surge.

There’s a clear partisan dimension to this story. According to Silverman, 17 out of the 20 fake news stories had information favoring Donald Trump. In contrast, a lot of the mainstream stories were pro-Clinton: pieces like “Trump’s history of corruption is mind-boggling” from the Washington Post and “I ran the CIA. Now I’m endorsing Hillary Clinton” from the New York Times.

The difference, of course, is that the latter stories are about things that really happened. A former CIA director really did endorse Hillary Clinton. You can argue with the analysis in the Washington Post’s story about Trump corruption, of course, but at least it discussed real events — like Trump’s donation to Florida Attorney General Pam Bondi, who dropped an investigation of Trump University shortly afterward.

When Silverman confronted Facebook with this data, the social media giant argued that focusing only on top articles gives a skewed picture of what ordinary Facebook users see.

“There is a long tail of stories on Facebook,” the spokesperson told BuzzFeed. “It may seem like the top stories get a lot of traction, but they represent a tiny fraction of the total.”

But this isn’t much of a defense. An enormous proportion of the very most popular news on Facebook seems to have been fake, reaching millions — probably tens of millions — of voters. That's millions too many.