Historical Graph of President Approval Ratings
Several things to note.
War Time Presidents seem to have extremes between the beginning and end of their terms. Look at Truman and Bush. In fact, with the exception of Nixon, the war time presidents have the highest approval ratings… Truman and the Bushes.
Clinton is the only one to end with a higher approval rating, but he really never got that high, seems to me he stayed in that mediocre range.
GW Bush got higher approval ratings than Kennedy. I always thought Kennedy was the most popular President.