 In the following table , " U.S. viewers ( million ) " refers to the number of Americans who viewed the episode on the night of broadcast . Episodes are listed by the order in which they aired , and may not necessarily correspond to their production codes . ‡ denotes an hour @-@ long episode ( with advertisements ; actual runtime around 42 minutes ) , and <unk> denotes an extended 75 @-@ minute episode ( with advertisements ; actual runtime around 52 minutes ) 
