Pew Research Center's Project for Excellence in Journalism
Ratios of commentary/opinion to news content on "news" networks:
MSNBC: 85% commentary/opinion, 15% news;
Fox News: 55% commentary/opinion, 45% news;
CNN: 46% commentary/opinion, 54% news.
Note that MSNBC's commentary/opinion consists overwhelmingly of leftist propaganda, tropes, and groupthink, while Fox presents a range of leftist, conservative, and libertarian viewpoints. (I never watch CNN so I have no idea what their ideological mix is.)