A new Gallup poll finds 42% of Americans, on average, identified as political independents in 2013, the highest measured in 25 years. Meanwhile, Republican identification fell to 25%, the lowest over that time span. At 31%, Democratic identification is unchanged from the last four years but down from 36% in 2008.

The percentage of Americans identifying as independents grew over the course of 2013, surging to 46% in the fourth quarter. That coincided with the partial government shutdown in October and the problematic rollout of major provisions of the healthcare law, commonly known as "Obamacare."

Democrats maintain their six-point edge in party identification when independents' "partisan leanings" are taken into account. In addition to the 31% of Americans who identify as Democrats, another 16% initially say they are independents but when probed say they lean to the Democratic Party. An equivalent percentage, 16%, say they are independent but lean to the Republican Party, on top of the 25% of Americans identifying as Republicans. All told, then, 47% of Americans identify as Democrats or lean to the Democratic Party, and 41% identify as Republicans or lean to the Republican Party.

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 in general.