"The partisan divide of cable news viewers."
A new Pew Research survey breaks down cable news network viewers by partisanship. CNN leads among Democrats, Fox leads Republicans, and MSNBC has the greatest percentage of independents:
CNN: 51% Democrats, 18% Republicans, 23% independents
MSNBC: 45% Democrats, 18% Republicans, 27% independents
Fox News: 33% Democrats, 39% Republicans, 22% independents