That Republican number had gone up from 2013, when only a third of Republicans thought that; the view increased among Democrats, too, though not to the same extent.
Feelings have bounced around on this a bit over the last eight years, and we saw a similar gap between the parties three years ago in 2011.
Looking back to 2006 and 2007 makes one suspect a little partisanship - and who's in power - plays into the mix here, too: back then Democrats were a bit more likely, or about as likely, to feel they were paying more than their fair share.
And by the way, we just went ahead and left off the percent of people who say they were paying less than their fair share. Hardly anyone - of any party - ever says that.