Washington (CNN) Barack Obama was catapulted into office eight years ago by what was, at the time, the most diverse electorate in history. The Americans who head to the polls to cast ballots for his successor are even more diverse.

Thirty-one percent of eligible voters will be racial or ethnic minorities, up from 29% in 2012, according to the Pew Research Center . And the share of non-Hispanic white voters eligible to vote will be the lowest in history, the continuation of a steady decline in white voters over the past three decades.

It's a stark reminder of the shifting demographics of the country: The Census Bureau projects that no one racial group will be a majority of the country by the year 2044. Republicans and Democrats looking to chart an electoral future as the country continues to grow browner and younger will have to take heed of these shifts.

The Republican presidential nominee has carried white voters in every presidential election since 1968 by shifting margins.

In the 1980 presidential election, white voters made up 88% of the electorate. That year, Ronald Reagan won 56% of non-Hispanic whites and captured the presidential election in a landslide. Four years later, against Walter Mondale, Reagan won them by 30 points, 66% to 34%. Since Reagan's time though, the white share of the electorate has declined by a few percentage points each presidential year.

Fast forward to 2012. Mitt Romney won a slightly larger share of non-Hispanic white voters --59%-- than Reagan did in his first term -- but lost the presidential race. Why? The share of the white vote was smaller -- 72% -- and Obama crushed Romney with non-white voters.

If trends hold, the 2016 share of the white vote will hit an all-time low

Most estimates suggest the white vote this year will be around 69%, an all-time low and a three percentage point decline in four years. That difference is more pronounced in a number of states that both candidates are targeting, including Pennsylvania, Ohio, Florida and North Carolina. All have eligible voting populations that are slightly less white than four years ago.

Why the white vote's shrinking

One reason is because overall, the white population in the United States is growing older and the younger generations of Americans are increasingly diverse, fueled largely by the growth of the Latino population in the US.

The pool of eligible voters follows along the same lines: According to an analysis by the Pew Research Center , non-Hispanic whites account for 76% of all eligible voters who died between 2012 and 2016. Racial and ethnic minorities account for 43% of the new eligible voters born in the US that turned 18.

Will non-white voters turn out in 2016?

As recently as 1996, white voters turned out at a higher rate than any other racial or ethnic group. But in 2012, the black voter turnout rate exceeded the white voter turnout rate, 66.2% to 64.1%.

But not all ethnic groups vote at such levels. While white voter turnout has decreased, Latinos and Asians have historically lagged behind both black voters and white voters. In 2012, 48% of eligible Latinos and 48% of eligible Asian voters cast ballots.