| 2020 | Democratic | 8,176,105 | 48.9% | | | Republican | 0 | 0.0% | | | Independent | 8,545,818 | 51.1% | |
| 2016 | Democratic | 6,660,555 | 50.6% | | | Republican | 0 | 0.0% | | | Independent | 6,508,909 | 49.4% | |
| 2008 | Democratic | 6,728,478 | 52.0% | | | Republican | 0 | 0.0% | | | Independent | 6,220,473 | 48.0% | |
| 2006 | Democratic | 2,483,597 | 29.5% | | | Republican | 0 | 0.0% | | | Independent | 5,926,800 | 70.5% | |
| 2004 | Democratic | 5,968,770 | 53.8% | | | Republican | 0 | 0.0% | | | Independent | 5,119,155 | 46.2% | |
| 2002 | Democratic | 3,947,217 | 57.8% | | | Republican | 0 | 0.0% | | | Independent | 2,883,234 | 42.2% | |
| 2000 | Democratic | 5,973,736 | 61.1% | | | Republican | 0 | 0.0% | | | Independent | 3,809,044 | 38.9% | |
| 1998 | Democratic | 3,071,422 | 37.6% | | | Republican | 0 | 0.0% | | | Independent | 5,092,446 | 62.4% | |
| 1978 | Democratic | 3,969,120 | 58.4% | | | Republican | 0 | 0.0% | | | Independent | 2,823,293 | 41.6% | |
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