Your basic math isn’t even right. This poll’s ideological totals are 46% conservative (somewhat or strong), not 42% you just said. Thats an overstatement by almost 10% (based off your own example). That is huge bias. It also shorts liberals 1%.
As far as the Dem v Repub affiliation numbers (Dems +7)
here are similar numbers (again from your own source, Gallup)
Democrats Increasing Their Edge in U.S. Party Affiliation
http://www.gallup.com/poll/190421/democrats-increasing-edge-party-affiliation.aspx
It shows a 6% gap.
This is the way it looked like in the last presidential election and 3 years of it from Rasmussen. I doubt much has changed but a few points here and there.
| October 31, 2012 | |||||||||||||
| Republican | Democrat | Other | R - D | Quarterly | |||||||||
| 2012 | |||||||||||||
| Oct | 39.1% | 33.3% | 27.5% | 5.8% | |||||||||
| Sep | 36.8% | 34.2% | 29.0% | 2.6% | 2.6% | ||||||||
| Aug | 37.6% | 33.3% | 29.2% | 4.3% | |||||||||
| Jul | 34.9% | 34.0% | 31.1% | 0.9% | |||||||||
| Jun | 35.4% | 34.0% | 30.5% | 1.4% | 1.8% | ||||||||
| May | 35.7% | 33.8% | 30.5% | 1.9% | |||||||||
| Apr | 35.1% | 33.1% | 31.8% | 2.0% | |||||||||
| Mar | 36.4% | 33.4% | 30.2% | 3.0% | 3.3% | ||||||||
| Feb | 36.0% | 32.4% | 31.6% | 3.6% | |||||||||
| Jan | 35.9% | 32.5% | 31.6% | 3.4% | |||||||||
| 2011 | |||||||||||||
| Dec | 35.4% | 32.7% | 32.0% | 2.7% | 1.1% | ||||||||
| Nov | 34.3% | 34.9% | 30.8% | -0.6% | |||||||||
| Oct | 34.3% | 33.1% | 32.6% | 1.2% | |||||||||
| Sep | 33.9% | 33.7% | 32.4% | 0.2% | -0.3% | ||||||||
| Aug | 33.5% | 33.0% | 33.5% | 0.5% | |||||||||
| July | 33.1% | 34.8% | 32.1% | -1.7% | |||||||||
| Jun | 34.4% | 34.7% | 31.0% | -0.3% | 0.9% | ||||||||
| May | 35.6% | 34.0% | 30.4% | 1.6% | |||||||||
| Apr | 34.8% | 33.5% | 31.7% | 1.3% | |||||||||
| Mar | 34.0% | 35.3% | 30.7% | -1.3% | 0.0% | ||||||||
| Feb | 35.1% | 34.3% | 30.6% | 0.8% | |||||||||
| Jan | 35.4% | 35.0% | 29.6% | 0.4% | |||||||||
| 2010 | |||||||||||||
| Dec | 37.0% | 33.7% | 29.3% | 3.3% | 0.6% | ||||||||
| Nov | 36.0% | 34.7% | 29.3% | 1.3% | |||||||||
| Oct | 33.4% | 36.3% | 30.3% | -2.9% | |||||||||
| Sept | 33.1% | 34.6% | 32.3% | -1.5% | -2.1% | ||||||||
| Aug | 33.8% | 35.0% | 31.1% | -1.2% | |||||||||
| July | 31.8% | 35.4% | 32.8% | -3.6% | |||||||||
| June | 33.0% | 35.4% | 31.6% | -2.4% | -3.3% | ||||||||
| May | 32.0% | 35.1% | 32.8% | -3.1% | |||||||||
| Apr | 31.6% | 36.0% | 32.5% | -4.4% | |||||||||
| Mar | 32.9% | 36.2% | 30.9% | -3.3% | -3.1% | ||||||||
| Feb | 32.1% | 35.1% | 32.9% | -3.0% | |||||||||
| Jan | 32.3% | 35.4% | 32.3% | -3.1% |
|
||||||||