New numbers from Gallup show that just 31 percent of Americans identified themselves as Democrats in 2010 — a five-point decrease from a year ago and the lowest percentage measured by the polling firm in 22 years. 

As Democratic identifiers decreased, the percentage of those calling themselves independents jumped to 38 percent — outpacing Democrats by seven points and Republicans by nine points. 

{mosads}Despite the decrease in Democratic identification, Gallup found that the percentage remains two points higher than Republican identifiers, which stands at 29 percent.  

The numbers were culled using data from 21 Gallup and USA Today/Gallup polls conducted over the past year with more than 25,000 interviews.

Gallup’s Jeffrey Jones writes that while there tends to be some variation in the numbers year to year, “the changes are typically not large.” He calls the five-point Democratic drop “notable.”

The GOP’s success in the 2010 midterms, in which the party won back control of the House by netting 63 seats, was aided by independents turning away from Democrats, which Jones said is the more troubling sign from Gallup’s numbers for the Democratic Party.

“The key to success in the 2012 elections may hinge on which party can win over the increasing number of independent voters,” Jones writes. “And it is quite possible that the pool of independents will expand in 2011, given that Gallup has seen an increase in the percentage of independents in each of the last five years after a midterm election.”