Peak viewership: Feb. 5, 2006, 37.88 million viewers
Lowest viewership: Dec. 5, 2013, 7.02 million viewers
There wasn't so much of a decline to Shonda Rimes' breakthrough show as there were two different incarnations of it.
There are the first four seasons when the show was an absolute mainstream phenomenon that permeated the culture and filled the ether with Isiah Washington's slurs, Patrick Dempsey's McDreaminess and Katherine Heigl and Sandra Oh's film careers. This is before Kate Walsh gets spun off into Private Practice, before Eric Dane becomes McSteamy and well before Rimes gets serious with Scandal.The reason this show survives is because much of what follows is what die-hard fans consider the good stuff. It's when the show propelled from its post-Super Bowl precipice, took a dramatic fall, dusted off and found some stability. Todd VanDerWerff at the A.V. Club provided a better summary of Grey's history and perseverance last summer than we can offer in this tiny space. But the fact Grey's Anatomy has never wavered from its basic premise that a medical drama could also serve as a window into interpersonal and -- more importantly -- romantic relationships has won it a loyal following. It dispels the wrongheaded belief that a show primarily about romance can't be taken seriously as a drama and has filled a long-neglected (and still neglected) niche in U.S. television. It may be fading, but it's a slow fade that could take a while. Dempsey and star Ellen Pompeo have stuck around for all 10 seasons and Sandra Oh is just getting around to leaving. The show itself, meanwhile, continues to put up ratings that fall just short of CBS' Two and A Half Men in their first half hour, but regularly beat that network's Bad Teacher in its second. It's also been regularly outperforming Fox's American Idol it its Thursday timeslot and putting the hurt on Fox's now-canceled Surviving Jack. Private Practice is gone and Scandal may be Rimes' headline grabber, but Grey's Anatomy's spirit and fanbase remain intact and won't be going anywhere anytime soon.