Report: More than 2.5 million have left major parties

Since the 2008 elections, more than 2.5 million people have given up membership in the Democratic and Republican parties, according to a USA Today analysis of voter registration statistics.

The analysis found that the number of registered Democrats has declined in 25 of the 28 states that register voters by party, while the number of registered Republicans has declined in 21 of those states.

Many voters have expressed frustration with the major parties and the government as a whole. In the latest CBS News poll, 56 percent of Americans said they are dissatisfied with the federal government, and 26 percent said they were angry toward the government; Congress' job approval rating, meanwhile, was just 11 percent.

The frustration appears to be driving more Americans to become independents. In the eight swing states analyzed by USA Today, Democratic registration fell 800,000, and GOP registration fell 350,000, while the number if independents increased 325,000.

The finding could be taken as evidence that Americans are increasingly open to a presidential candidate outside the two-party system. Former New Mexico Gov. Gary Johnson is preparing to announce a run on the Libertarian ticket after a frustrating run at the GOP nomination, and a group called Americans Elect is working to get on the ballot in all 50 states in order to give voters the choice of a ticket that doesn't come from one of the two parties.

According to USA Today, there are 42 million registered Democrats in the country today, along with 30 million Republicans and 24 million independents.