Constitutionally, the number of electors in each state is equal to the number of members of Congress to which the state is entitled, while the 23rd Amendment grants the District of Columbia the same number of electors as the least populous state, currently three.   

Maine (since enacting a state law in 1969) and Nebraska (since enacting a state law in 1992) have awarded one electoral vote to the winner of each congressional district, and two electoral votes statewide.  

77% of Maine voters and 74% of Nebraska voters support a national popular vote.

Nebraska in 2008 was the first time any state in the past century gave one electoral vote to the candidate who did not win the state. 

2016 is the first time an electoral vote in Maine was given to the candidate who did not win the state.