For at least three years, the Associated Press-Roper-GfK poll has been periodically asking respondents, “Do you consider yourself a Democrat, a Republican, an independent, or none of these?” The September 2012 poll, taken between September 13-17, shows these results on page 34:
None of these 17%
don’t know 1%
refused, less than 1%
During the last three years, the range of Democrats has varied from a high of 35% to a low of 28%. The range of Republicans have been 32% to 18%. The range of independents has varied from 33% to 24%. The range of “none of these” is 7% to 20%.