| 2022 | Democratic | 6,355,910 | 59.9% | | | Republican | 4,249,387 | 40.1% | |
| 2018 | Democratic | 5,362,635 | 52.0% | | | Republican | 0 | 0.0% | | | Independent | 4,946,923 | 48.0% | |
| 2014 | Democratic | 4,038,165 | 57.5% | | | Republican | 2,981,951 | 42.5% | |
| 2010 | Democratic | 4,765,400 | 50.6% | | | Republican | 3,540,626 | 37.6% | | | Other | 1,116,826 | 11.9% | |
| 2006 | Democratic | 3,204,536 | 38.5% | | | Republican | 4,233,986 | 50.8% | | | Other | 890,875 | 10.7% | |
| 2002 | Democratic | 3,346,937 | 46.5% | | | Republican | 2,998,243 | 41.6% | | | Other | 855,249 | 11.9% | |
| 1998 | Democratic | 3,519,453 | 43.8% | | | Republican | 4,006,762 | 49.9% | | | Other | 509,822 | 6.3% | |
| 1994 | Democratic | 3,567,996 | 43.4% | | | Republican | 4,015,858 | 48.8% | | | Other | 641,633 | 7.8% | |
| 1990 | Democratic | 3,770,717 | 52.2% | | | Republican | 2,736,577 | 37.9% | | | Other | 713,214 | 9.9% | |
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