The Electoral College will officially elect Donald Trump as the next president today, but it’s important to remember that he received fewer votes from Americans than Hillary Clinton — something more than half of Republicans don’t know.

An updated count by the Cook Political Report shows Trump lost the popular vote by about 2.1 percentage points. Meanwhile, Trump racked up 306 electoral voters — 14 percent more than Clinton.

Don’t let recent history fool you into thinking this has happened a lot. Sure, we saw this in 2000, when George W. Bush received about 500,000 fewer votes than Al Gore but still won the election. But this is only the fourth times in American history that someone has won the Electoral College, but lost the popular vote.

John Quincy Adams also lost the popular vote in 1824. Since none of the four candidates received 50 percent of the electoral vote, the House of Representatives decided who would be president — and Adams came out ahead.

There is only one president-elect has lost the popular vote by a wider margin than Trump. The widest margin was in 1876, when Rutherford B. Hayes won a controversial election that took months to settle, even though he lost the popular vote to Samuel Tilden by 3 percentage points.

Shifting demographics might make this more common

This might be historically rare, but shifting demographics means this might become more common. It’s more likely that we’ll see scenarios that change the popular vote, but don’t change the electoral vote. Here are a handful of them:

Gaining ground in safe Democratic states: Barack Obama won the 2012 election around a coalition of minorities and young voters. An overwhelming percentage of these groups voted for Obama the last time around with strong turnout. But those groups, specifically Latinos and Asians, are concentrated in safe Democratic and safe Republican states like California, Texas, and New York. She gained ground in all those states compared to Obama in 2012, but that doesn’t help with electoral math. Gaining ground in safe Republican states: The other factor is that Democrats gained ground from 2012 in states that are usually safe Republican states — places like Texas, Georgia, Utah, and Idaho. (Check out this great New York Times map, which shows how the votes shifted from 2012.) It may put these states into play in future elections, but for this one it increased Clinton’s popular vote margin while not helping her with the electoral math. Losing a little ground with minorities and young people in swing states: Meanwhile, Clinton lost ground in swing states, and early exit poll analysis indicates that turnout among the minorities and young people was lower, and that Clinton won a smaller ratio of those groups than Obama. This is important because, when it comes to the popular vote, these swing states are decided by a few hundred thousand votes — and the Electoral College doesn’t let you make them up with gains in the safe states.

No matter what the outcomes, the Electoral College is a terrible system

Of course, this separation between the raw vote totals and the election winner is happening because of a very American system called the Electoral College, which requires presidential candidates to win states rather than voters.

The US is a democratic republic, so it’s not necessarily a bad thing that it’s not a direct election. Rather, we have one where we elect representatives to vote for us — in this case, the members of the Electoral College. But there are some flaws to the way this system is built.

First off, it means that if a candidate wins a state in a landslide or in a close race, they get the same number of votes either way. This means in states that are safe Republican or Democrat states, there is little mystery what the results of the election will be, regardless of who you vote for.

Second, some voters have a lot more power than others. For example, a vote in Wyoming carries about 3.5 times more power than one in Texas, because, no matter how small a state, it is guaranteed at least three electoral votes — two for the senate seat, and at least one for the house seat.

(Vox’s Andrew Prokop explains more in-depth here why the Electoral College is a bad system.)

Correction: A previous headline said Trump was the fourth president to get fewer votes than his opponent, but he’s actually the fourth to lose the popular vote yet win the Electoral College. This distinction is important because John Quincy Adams also lost the popular vote in 1824, but since none of the four candidates received 50 percent of the electoral vote, the House of Representatives decided who would be president and chose him.

Watch: The bad map we see every election