According to Gallup's survey of 18,000 voters, 42 percent identify themselves as independents, 31 percent as Democrats and 25 percent as Republicans.
The percentage of voters who consider themselves Democrats has remained about the same since 1988, Gallup discovered, but independents have grown from about 33 percent to 42; and the percentage of those identifying themselves as Republicans has dropped from about 31 percent to 25.
Historically, it has not been unusual for independents to be the largest group of voters but voters' distaste for both major parties appears to be stronger than ever.
"The rise in political independence is likely an outgrowth of Americans' record or near-record negative views of the two major U.S. parties, of Congress, and their low level of trust in government more generally," Gallup said.
What do the numbers mean for this year's election results? While more identify themselves as Democrats than Republicans, Democratic votes alone cannot win elections.
"The increased independence adds a greater level of unpredictability to this year's congressional midterm elections," Gallup concluded. "Because U.S. voters are less anchored to the parties than ever before, it's not clear what kind of appeals may be most effective to winning votes. But with Americans increasingly eschewing party labels for themselves, candidates who are less closely aligned to their party or its prevailing doctrine may benefit."
It is unlikely that increasing voter independence will result in the election of a large number of declared independents to serve in Washington, D.C.
Only two U.S. senators were elected as independents. They are Sen. Bernie Sanders of Vermont and Sen. Angus King of Maine, both of whom decided to join the Senate Democratic Caucus.
There is no elected independent in the U.S. House of Representatives.