But it may become more and more common, given shifting demographics.
Source: Trump will be the 4th president to win the Electoral College after getting fewer votes than his opponent – Vox
Donald Trump won the electoral college, but when all the votes are counted, it’s likely he will have received fewer votes from Americans than Hillary Clinton.
It will take time for the exact numbers to be counted, but the New York Times projects Trump to lose the popular vote by about 1.3 percentage points. Meanwhile, Trump is most likely to rack up 306 electoral voters — 14 percent more than his opponent.
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 — and it might not be the last.
(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.)
In fact, only one president-elect has lost the popular vote by a wider margin than Trump. In 1876, 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.
Read more here: http://www.vox.com/policy-and-politics/2016/11/9/13572112/trump-popular-vote-loss