The number of Americans not affiliated with either major political party inched up nearly a full point during June, with both Republicans and Democrats contributing to the increase. However, the larger picture is one of partisan stability over the past four months.

In June, 38.9% of American adults considered themselves Democrats. That’s down half-a-point from last month.

As for the GOP, 32.2% now claim an affiliation with the party. That’s down four-tenths-of-a-point from a month ago.

The number of unaffiliated adults grew from 28.0% to 28.9%.

Over the past four months, the partisan alignments have all stayed with a range of a single percentage point or less.

The number of Democrats has stayed between 38.7% and 39.4%. The number of Republicans has stayed between 32.2% and 33.2%. As for unaffiliateds, they have ranged from 28.0% to 28.9%.

Rasmussen Reports tracks this information based upon telephone interviews with approximately 15,000 adults per month and has been doing so since November 2002. The margin of error for the full sample is less than one percentage point, with a 95% level of confidence.
While Democrats now enjoy a 6.7-percentage-point edge over Republicans, they averaged a seven-point advantage during the first three months of 2009.

The partisan identification numbers shift little from month-to-month, but they document just how dramatically the political environment has changed over the past four years. In January 2005, as President Bush was inaugurated for his second term in office, the Democrats enjoyed just a one-percentage-point advantage over the GOP.

Keep in mind that figures reported in this article are for all adults, not Likely Voters. Republicans are a bit more likely to participate in elections than Democrats.

Data from our monthly partisan identification survey is used to set weighting targets for other Rasmussen Reports surveys. The targets are based upon results from the previous three months.

The Rasmussen Reports daily Presidential Approval Index shows that President Obama continues to earn favorable reviews early in his administration. However, his numbers are down slightly from earlier in the year.

The gap between Democrats and Republicans has closed on 10 key issues tracked by Rasmussen Reports and on the Generic Congressional Ballot.

See History of Party Trends from January 2004 to the present.