The party identification of American voters was one of the most hotly debated topics among analysts before the 2012 presidential election. Many Republicans thought there were roughly equal numbers of Democrats and Republicans, and so doubted polls showing President Obama with the lead.

In the end, the polls were right. This week, a Pew Research report based on about 25,000 interviews in 2014 took a new measure of partisanship. Here are the most interesting findings:

Despite the president’s sagging approval ratings in 2014 and the strong Republican performance in the midterm elections, the Democrats retain a nine-point advantage among adult Americans who lean toward a party identification, 48 percent to 39 percent.

The tally is nearly unchanged from the 10-point Democratic advantage in 2012, when President Obama won re-election.