big bang and ncis tops most viewed prime time TV shows

The Big Bang and NCIS  are the most watched TV shows ( prime time in US) since the last  2 years ( 2014-2015)

At the end of its eighth season, the CBS sitcom led all primetime shows, broadcast or cable, with 21.3 million weekly viewers (including seven days of DVR use and video-on-demand), a hair above two more perennial ratings faves: NBC's Sunday Night Football and CBS's NCIS, both with 21 million viewers . NCIS  is a sitcom based   on  Naval Criminal Investigative services .

 The Big Bang Theory  created by Chuck Lorre and Bill Prady had  first  premiered on CBS on September 24, 2007.