The American public's confidence in its lawmakers in Washington has reached a historic low not just for Congress but compared to any major U.S. institution, a Gallup poll released Thursday showed. Only 7 percent of Americans surveyed said that they have "a great deal" or "quite a lot" of confidence overall in Congress, down from 10 percent last year, the polling firm said. "This is the lowest confidence score Gallup has recorded for any institution - ever," Gallup said in a statement. "This is also the first time Gallup has ever measured confidence in a major U.S. institution in the single digits." The findings could lead to even more trouble for incumbent lawmakers in November's election. Already, several longtime lawmakers have faced serious challenges, including outgoing House Majority Leader Eric Cantor who lost his Republican primary race in Virginia last week. Confidence in U.S. lawmakers has been falling ever since Gallup began surveying the public about Congress in 1973. At that time, 42 percent of those polls responded positively.