In September, the number of Americans who consider themselves to be Republicans increased a percentage point from 33.2% in August to 34.4% in September.

During that same period, the number of Democrats declined slightly from 38.9% to 38.4.%. The remainder, 27.2%, are not affiliated with either major political party.

That gives the Democrats a net advantage of 4.0 percentage points, down from 5.7 percentage points in August. However, it must be noted that the beginning of the month featured the Republican National Convention. Later in the month, the partisan identification was a bit more favorable for the Democrats.

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 Democrats today enjoy a much bigger advantage today than they did when votes were cast in Election 2004 (see history from January 2004 to present).

In 2004, the Democrats began the year with a 2.3 percentage point edge over the GOP. That grew to 4.0 points by March before moving in the Republican direction for the rest of the year. By Election Day in 2004, the edge for Democrats was a mere 1.6 percentage points.

In 2006, the Democrats began the year with just a 1.6 percentage point advantage. That grew to 6.1 percentage points by November.

These results are based upon tracking surveys of 15,000 adults per month. The margin of sampling error for the sample is less than one percentage point, with a 95% level of confidence.

For Election 2008, Rasmussen Reports is updating its partisan weighting targets for the daily Presidential Tracking Poll each week. For polling data released during the week of September 28-October 4, 2008, the partisan weighting targets used by Rasmussen Reports will be 39.0% Democratic, 33.4% Republican, and 27.6% unaffiliated. For the preceding week, the partisan weighting targets were 39.0% Democratic, 33.5% Republican, and 27.5% unaffiliated.

Please keep in mind that figures reported in this article are for all adults, not Likely Voters.

The Rasmussen Reports daily Presidential Tracking Poll now shows Obama with a growing advantage heading into the final month of the campaign. The same is true when you look at the Electoral College. Democrats continue to have a significant advantage on 10 key issues tracked by Rasmussen Reports and lead on the Generic Congressional Ballot.