Former President Barack Obama waves to reporters after returning to the White House on board Marine One Sept. 3, 2015 in Washington, D.C. Getty Images

President Donald Trump's inauguration — and Barack Obama's departure — may have you longing for the old days. American history is full of well-loved presidents: George Washington, for example, was unanimously elected in 1789, and Franklin Roosevelt spent four terms in office in the 1930s and '40s.

Trump's approval rating, which as of Friday was 36 percent, has put his predecessors' popularity in the spotlight. A Quinnipiac University poll out Thursday revealed that 30 percent of voters thought Ronald Reagan, in office from 1981 to 1989, was the best president of the past 70 years. Obama came in second with 29 percent support, and John Kennedy was third with 12 percent.

The Quinnipiac poll found that Richard Nixon, who resigned from office, was considered the worst president in the modern era, followed by Obama and George W. Bush.

Those rankings were narrow, though, only including commanders-in-chief since World War II. For presidential rankings throughout all of history, you have to back a bit further, to 2010, when the Siena College Research Institute conducted its traditional survey of presidential scholars to identify the best U.S. leaders.

Franklin Roosevelt won that contest, scoring high in categories like party leadership, communication ability, handling of the economy and foreign policy accomplishments. In second place was his distant cousin Theodore Roosevelt, the 26th president, who did particularly well in categories like court appointments, imagination and willingness to take risks, according to Siena College data.

Also in the top five were Abraham Lincoln, Washington and Thomas Jefferson.

"In nearly 30 years, the same five presidents have occupied the first five places with only slight shuffling," Douglas Lonnstrom, a statistics professor at Siena College, said in a 2010 news release. "Despite decades of new research on former presidents and the accomplishments or lack thereof of the current chief executives, scholars display amazingly consistent results."

Translation: Americans will just have to wait to see what Trump's impact will be.