The three-hour performance of the classic Rodgers & Hammerstein musical delivered 18.5 million viewers and a great 4.6 rating among adults 18-49. Excluding sports, this is NBC’s biggest Thursday in the adult demo since the ER finale in 2009 and most-watched Thursday since the Frasier finale in 2004. Obviously, it’s also far and away NBC’s strongest non-sports Thursday performance this season; the network has had all sorts of ratings headaches on this night given its troubled comedy block. Sound of Music was Thursday’s most-watched show and tied CBS’ Big Bang Theory in the demo to win the evening.