http://tvbythenumbers.zap2it.com/20...viewership-for-week-ending-may-4-2014/260772/
Total Day Average Viewers (Live+SD)
Network (000s), NICK 1523, TNT 1521, DSNY 1200, ADSM 1159, USA 1131, NAN 1027, FOXN 955, TOON 876, HIST 827, ESPN 737, HGTV 696, A&E 655, ID 607, TBSC 594, FX 547, DISC 529, FOOD 527, LIFE 499, FAM 493, SPK 479, TLC 452, HALL 452, AMC 451
NICK / NAN (Nick at Night) are the same, TOON (Cartoon Network) and ADSW (Adult Swim) are the same.
So your top cable are: Nickelodeon, TNT, Disney, Cartoon Network, USA, Fox News, History Channel, ESPN, HGTV, A&E, Investigation Discovery, TBS, FX, Discovery Channel, Food Network, Lifetime, ABC Family, Spike TV, TLC, Hallmark Channel, and AMC.
Walt Disney Co is invested in: Disney Channel, History Channel, ESPN, A&E, Lifetime, ABC Family.
Viacom Media is invested in: Nickelodeon, Spike TV
Discovery Communications is invested in: Investigation Discovery, Discovery Channel, TLC
Turner Broadcast is invested in: TNT, Cartoon Network, TBS.
Scripps Networks is invested in: HGTV, Food Network
So your top 21 (combining Nickelodeon programming and Cartoon Network programming) cable stations are almost all controlled by just five media providers.
*edit* I didn't include the over-the-air networks.