Independent voters increase in key swing states

— -- Democrats are losing ground in voter registration in six key battleground states as more voters elect to register as independents, according to a new Bloomberg News analysis of state voter records.

As Bloomberg's John McCormick reports:

The collective total of independents grew by about 443,000 in Colorado, Florida, Iowa, Nevada, New Hampshire and North Carolina since the 2008 election, according to data compiled by Bloomberg from state election officials.

During the same time, Democrats saw a net decline of about 480,000 in those six states, while Republicans--boosted in part by a competitive primary earlier this year--added roughly 38,000 voters in them, the analysis shows.

The shift comes four years after President Barack Obama won the White House in 2008 thanks in part to wide support among independents. But indy voters swung back toward Republicans during the 2010 midterms, helping the GOP retake the House—a shift that may help Romney.

According to the latest Washington Post/ABC News poll, Romney holds a 14-point lead over Obama among independent voters nationally.