Most political and media commentators have at this point installed Donald Trump as the GOP front-runner on the eve of the first actual voting set to begin on Monday in Iowa. But this narrative tends to obscure the fact that Trump is the most unpopular candidate of either party when the entire U.S. population is taken into account -- and that he has a higher unfavorable rating than any nominated candidate from either of the two major parties going back to the 1992 election when we began to track favorability using the current format.

At this point (two-week average through Jan. 27), 33% of Americans view Trump favorably and 60% unfavorably. It's that 60% unfavorable figure that I can focus on here.

Hillary Clinton currently has a 52% unfavorable rating among all Americans, while Jeb Bush is at 45%, Chris Christie 38%, Ted Cruz 37%, Marco Rubio 33%, Bernie Sanders 31% and Ben Carson 30%. Trump's 60% is clearly well above all of these. Putting his favorable and unfavorable ratings together yields a net favorable of -27 for Trump, far above the -10 for Clinton and for Bush, the next lowest among the major candidates.

I wanted to see how Trump's unfavorable played out in the context of previous elections, so I went back to look at the unfavorable ratings of the major-party candidates from 1992 through the current election. The bottom line is that Trump now has a higher unfavorable rating than any candidate at any time during all of these previous election cycles, and that conclusion takes into account the fact that unfavorable ratings tend to rise in the heat of a general election campaign as the barbs, negative ads and heightened partisanship are taken to their highest levels. Gallup routinely reports favorable ratings based on national adults, but some of the favorable ratings in the final months of an election year that I discuss below are based on registered voters.

Bill Clinton's highest unfavorable rating in the 1992 election was 49% (in April and July of that year). His opponent, George H.W. Bush, came closest to Trump's current unfavorable rating in October 1992, as Election Day approached and he received a 57% unfavorable rating in Gallup's tracking.

In 1996, Clinton's highest unfavorable was even lower, at 44%, while his opponent, Bob Dole, never rose above a 47% unfavorable.

The 2000 election, as now, was for an open seat, pitting the sitting Vice President Al Gore against Texas Gov. George W. Bush. Gore's highest unfavorable was 42% before the November voting, rising to one reading of 52% unfavorable in December 2000 as the disputed popular vote count in Florida continued. Bush was more popular; his unfavorable rating in 2000 never rose above 41% before the election, although, like Gore's, it edged up during the recount.

When Bush was running for re-election in 2004, his highest unfavorable was 47%, while John Kerry's highest was 45%. (Both men did receive higher unfavorable ratings later on; I'll return to Bush's story below.)

In 2008, Barack Obama maintained a very popular image, with an unfavorable rating maxing out at 37%, while John McCain also remained popular with a maximum unfavorable of 44%. And when running for re-election in 2012, Obama's unfavorable crept up to 48%, while his opponent, Mitt Romney, also maxed out at 48%.

Looking across all of these candidates' unfavorable ratings outside of election years yields this conclusion: Only one of them, George W. Bush, ever had an unfavorable rating of 60% or higher. For Bush, his unpopularity crested in his final lame-duck year in office, with an unfavorable rating that hit 66% in April 2008.

By comparison, Bill Clinton's highest unfavorable rating in Gallup's history of rating him has been 59% in March 2001 after he left office amid criticism of his pardons and issues relating to White House furniture. The highest unfavorable for his wife, Hillary, came in that same March 2001 poll -- at 53% -- a figure she has matched several times in the current campaign.

One candidate I haven't mentioned here is Ross Perot. The maverick third-party candidate's unfavorable rating did reach above 60% at points in both the 1992 and 1996 campaigns, no doubt because neither party had any loyalty toward him. Perot got 19% of the popular vote in 1992 and 8% in 1996.