Donald Trump is starting his presidency with even approval ratings in Gallup's long-standing tracking poll, a figure that improves on his favorability rating but trails where other presidents have begun their administrations.

Gallup released its first figures since Trump's inauguration on Friday for its daily tracking poll, with 45 percent of American adults saying they approve of the job he is doing as president and 45 percent of Americans saying they disapprove.

Trump is starting with the smallest share of Americans saying they approve of his job performance in Gallup's poll going back to President Harry Truman. Before Trump, Presidents Ronald Reagan and George H.W. Bush started with the lowest percent approval, at 51 percent each.

Still, that's better than the 40 percent of Americans who say they hold a favorable opinion of the new president and 55 percent who hold unfavorable views, an unusual reversal of the prevailing trend since the polling organization began asking about favorability during President George H.W. Bush's administration. Gallup has noted in the past that Americans tend to think more highly of their commanders in chief on a personal level than they do of their job performance.

While most presidents ended their time in office with lower overall approval than when they began, both Reagan and Bush left office having improved on their starting point; Reagan left office with a 63 percent approval rating and Bush with 56 percent approving. President Bill Clinton, who began his first term at 58 percent approval and left with 66 percent approval, is the only other president who managed to leave office with a higher share of the country approving of his job performance than when he moved into the White House.

But unlike Trump, Reagan and Bush started out with much lower disapproval ratings, at 13 percent and 6 percent, respectively, when taking office.