Congress is on pace to tie a record. But it's not one that will make members proud.

With Congress averaging a 15 percent approval rating so far this year according to Gallup, 2013 is on pace to tie 2012 as the lowest year for Congress since Gallup started measuring the public's approval of the legislative body four decades ago.

Congress hasn't been a very popular institution during that time, as the chart below shows. But things haven't been nearly as bad as they have been in recent years.

For context, 2013 is poised to be the fourth year in a row that the average approval rating of Congress has been under 20 percent. And before 2008, it dipped below 20 percent only twice in 31 years. That's right. Just twice.

That speaks volumes about the historic nature of the disapproval with which Americans view Congress right now.