On some occasions, applause occurs in the middle of an event. The President of the United States, in his State of the Union address, is often interrupted by applause; tracking the number and duration of such interruptions has become a trend on various television news channels. It is often customary for jazz performers to receive applause in the middle of a tune, after completing an improvisational solo. It is also typical to applaud at the end of a musical number in a musical theatre piece.