Story highlights There are about 6,000 more Democrats registered than Republicans in Colorado

More Coloradans are registered as "unaffiliated" than with either party

(CNN) For the first time in 30 years, Democrats have the voter registration advantage in the battleground state of Colorado, edging ahead of Republicans in a key metric of party strength with one month to go before Election Day.

According to new numbers released Monday by the Colorado Secretary of State, there are about 6,000 more Democrats on the rolls than Republicans. There are 998,845 registered Democrats and 992,944 registered Republicans. That being said, there are still more independent voters in the state -- 1,080,438 Coloradans are currently registered as "unaffiliated."

The GOP lead has been shrinking in recent months -- it was roughly 12,000 in August and 2,700 in September.

Republicans have enjoyed an edge in voter registration in Colorado since 1986, according to an analysis of decades of publicly available voter registration records. The numbers fluctuate on a monthly basis, but the GOP advantage was about 177,000 in November 2004, when George W. Bush carried the state. Republicans continued to lead Democrats on the voter rolls even as Barack Obama won Colorado in 2008 and again in 2012.

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