End-of-term approval ratings for presidents are valuable in forecasting voter preferences in the following election. The higher a president's job approval ratings are at the end of his term, the more likely it is a candidate from his party will succeed him in the White House. That, of course, is not always the case. Democratic President Bill Clinton left office with a relatively high approval rating in 2000, but his impeachment during a second term harmed the chances that his vice president, Al Gore, would succeed him. Republican George W. Bush narrowly won the White House in the 2000 election, though he lost the popular vote. President Barack Obama's sound approval rating may not be an indicator of Democrat Hillary Clinton's chances in 2016, either. The last time voters elected a Democrat to the White House after a president from the same party had just served a full term was in 1856, before the Civil War. So which presidents were the most popular upon leaving the White House? And what were their end-of-term job approval ratings? Here's a look at the popularity of 11 modern U.S. presidents at the times they left office using data from the Gallup organization, a reliable public-opinion firm that has tracking job approval ratings for decades.

01 of 11 Ronald Reagan - 63 Percent (Photo by Keystone/CNP/Getty Images) Republican President Ronald Reagan was one of the most popular presidents in modern history. He left the White House with a job approval rating of 63 percent, support that many politicians can only dream of. Only 29 percent disapproved of Reagan's work. Among Republicans, Reagan enjoyed a 93 percent approval rating.

02 of 11 Bill Clinton - 60 Percent Mathias Kniepeiss/Getty Images News President Bill Clinton, one of only two presidents to ever be impeached, left office on January 21 with 60 percent of Americans saying they approved of his job performance, according to the Gallup organization. Clinton, a Democrat, was impeached by the House of Representatives on December 19, 1998, for allegedly misleading a grand jury about his extramarital affair with Lewinsky in the White House, and then persuading others to lie about it, too. That he left office on such good terms with a majority of the American public is a testament largely to the strong economy during his eight years in office.

03 of 11 John F. Kennedy - 58 Percent Central Press/Getty Images Democratic President John F. Kennedy, who was assassinated in Dallas in November 1963, died at a time when he had the support of a solid majority of support from American voters. Gallup tracked his job-approval rating at 58 percent. Fewer than a third, 30 percent, of Americans viewed his tenure in the White House unfavorably in a poll conducted in October 1963.

04 of 11 Dwight Eisenhower - 58 Percent Bert Hardy/Getty Images Republican President Dwight Eisenhower left office in January 1961 with a job approval rating of 58 percent. Only 31 percent of Americans disapproved.

05 of 11 Gerald Ford - 53 Percent Chris Polk/FilmMagic Republican Gerald Ford, who served only a partial term following the resignation of Richard Nixon after the Watergate scandal, left office in January 1977 with the support of a majority of Americans, 53 percent. That he took office amid such extraordinary circumstances and was able to maintain such support is noteworthy.

06 of 11 George H.W. Bush - 49 Percent Jason Hirschfeld/Getty Images News Republican George H. W. Bush left office in January of 1993 with the support of 49 percent of voters at the time, according to Gallup. Bush, one of the few presidents to run for and lose re-election, was "unable to withstand discontent at home from a faltering economy, rising violence in inner cities, and continued high deficit spending," according to his official White House biography.

07 of 11 Lyndon Johnson - 44 Percent Central Press/Getty Images Democratic President Lyndon B. Johnson, who took office following the assassination of John F. Kennedy, left office in January 1969 with a job approval rating of just 44 percent, according to Gallup. Roughly the same portion of Americans disapproved of his tenure in the White House, during which time he ramped up the country's involvement in the Vietnam War.​

08 of 11 George W. Bush - 32 Percent Hulton Archive - Getty Images Republican George W. Bush left office in January 2009 as one of the most unpopular presidents in modern history, largely because of his decision to invade Iraq in what became an increasingly unpopular war by the end of his second term. When Bush left office, he had the support of fewer than a third of Americans, according to the Gallup organization. Only 32 percent viewed his job performance favorably and 61 percent disapproved.

09 of 11 Harry S. Truman - 32 Percent (Photo by Underwood Archives/Getty Images) Democratic President Harry S. Truman, who won the presidency despite his meager upbringing, left office in January 1953 with a job approval rating of just 32 percent. More than half of Americans, 56 percent, disapproved of his work in office.

10 of 11 Jimmy Carter - 31 Percent Dominio público Democrat Jimmy Carter, another one-term president, suffered politically from the hostage-taking of U. S. embassy staff in Iran, which dominated the news during the last 14 months of Carter's administration. His campaign for a second term in 1980 was also bogged down by high inflation and a troubled economy. By the time he left office in January of 1981, only 31 percent of Americans approved of his job performance and 56 percent disapproved, according to Gallup.