An average of 43 percent of Americans now self-identify as independent of any political party, the highest percentage since Gallup began asking the question in 1988, a new analysis by Gallup revealed.

That's up from 35 percent in 2008, and the previous high of 39 percent in 1995 and 1999.

Only 30 percent of Americans identify as Democratic, and 26 percent as Republicans, according to Gallup.

It signals ever-increasing discontent with both the Democratic and Republicans parties and reinforces a recent Gallup poll which found that most Americans believe Government/Congress/Politicians were the most important problem facing the U.S. in 2014.

The decline in party identification is likely due to divided party control of the federal government resulting in Republican and Democratic lawmakers failing to live up to expectations of their constituents, suggests Gallup's Jeffrey Jones.

"Trust in the government to handle problems more generally is the lowest Gallup has measured to date, and Americans' favorable ratings of both parties are at or near historical lows," Jones said. "Thus, the rise in U.S. political independence likely flows from the high level of frustration with the government and the political parties that control it."

Both parties have suffered from the rise in political independence, but Democrats have lost more support than Republicans, Jones said.

"Over the last six years, Democratic identification has fallen from 36% -- the highest in the last 25 years -- to 30%. Meanwhile, Republican identification is down from 28% in 2008 to 26% last year."

To determine the number of independents, Gallup examined data from 15 separate telephone polls conducted throughout 2014.

The organization has been asking party identification questions via telephone since 1988, and before that, it asked the question through in-person polling.

While Gallup acknowledges that that data compiled in telephone polls since 1988 is not directly comparable to data gathered in-person prior to then, Jones says that "it is safe to say the average 30 percent identifying as Democrats last year is the lowest since at least the 1950s."

Republican identification, on the other hand, increased one point since 2013, from 25 percent to 26 percent, but is still four points lower than in 2008.

"Not since 1983, the year before Ronald Reagan's landslide re-election victory, have fewer Americans identified as Republicans," Jones said.