A new Gallup poll reveals that the number of Americans who identify themselves as independents has soared in recent years.

In 2013, 42% of Americans identified as political independents, up a few percentage points from 2012. Democrats hold a six-point lead in party identification, 31-25%. That's the lowest percent Republicans have seen in 25 years.

When you factor in those independents who lean toward one party or the other, Democrats retain their six-point advantage (47%-41%).

The share of Americans who identify as Republicans has steadily fallen since it peaked at 34% in 2004.

Gallup conducted more than 18,000 interviews during 13 separate polling periods in 2013. Throughout the year itself, the number of independents grew dramatically, from 37% in the first quarter to 46% in the fourth. This happened as Republicans killed popular gun and immigration legislation and shut down the government, while Obamacare's federal exchange website had a catastrophic launch and Democrats were forced to deal with the fall-out of President Obama's lie that "if you like your plan, you can keep it."

No wonder fewer and fewer people want to identify with either party.

Here's party identification historically:

And here it is over the course of 2013: