Just 47 percent of adults in the U.S. say they are "extremely proud" to be American, the lowest share since polling organization Gallup first started asking that question nearly two decades ago. 

And that's down ten points in just the last five years, from 57 percent in 2013. 

The decline has largely been among Democrats. Only 32 percent of Democrats told pollsters they are "extremely proud" to be American — down from 56 percent in 2013. 

About four-in-ten independents (42 percent) express the highest level of pride in their American identity, down from 50 percent five years ago. 

The opposite trend is true among Republicans. Now, nearly three-quarters of Republicans (74 percent) say they're extremely proud to be Americans, up slightly from 71 percent in 2013.