https://phys.org/news/2018-11-crackdown-junk-news-flourishes-social.html

In analyzing some 2.5 million tweets and 6,986 Facebook pages over a 30-day period, the study found that less than five percent of the sources referenced on social media were from public agencies, experts or political candidates themselves.

"We found that the proportion of junk news circulating over social media has increased in the US since 2016, with users sharing higher proportions of junk news than links to professional content overall," the report released Thursday said.