President Bush's approval ratings over the last eight years have been characterized by "extreme highs and lows," according to Gallup. "His record 90% approval rating early in his presidency following the Sept. 11 terrorist attacks stands in stark contrast to his sub-30% approval ratings during most of his final year in office, which rank among the lowest ratings ever measured," Gallup's Jeffrey M. Jones writes.

When averaging Bush's ratings, he ranks seventh out of 11 post-World War II presidents for highest approval rating -- just below Reagan and above Nixon. Bill Clinton ranks fourth, just below Bush's father.