| 2018 | 2018 | 2018 | 2018 | 2016 | 2016 | 2016 | 2016 | 2016 | 2016 | 2016 | 2016 | 2016 | 2016 | 2016 | 2016 | 2016 | 2016 |
|---|
| | Rauner | Ives | Harold | Grasso | Trump | Cruz | Kasich | Rubio | Carson | Bush | Paul | Christie | Huckabee | Fiorina | Santorum | Kirk | Marter | Munger |
|---|
| 1st Congress | 46.65% | 53.35% | 54.95% | 45.05% | 48.41% | 24.77% | 16.45% | 8.14% | 0.79% | 0.59% | 0.35% | 0.20% | 0.13% | 0.09% | 0.08% | 66.76% | 33.24% | 100.00% |
| 2nd Congress | 49.57% | 50.43% | 54.56% | 45.44% | 44.13% | 29.28% | 14.94% | 8.44% | 1.14% | 0.94% | 0.43% | 0.27% | 0.22% | 0.10% | 0.11% | 68.14% | 31.86% | 100.00% |
| 3rd Congress | 49.44% | 50.56% | 55.46% | 44.54% | 51.34% | 22.19% | 16.53% | 8.16% | 0.44% | 0.60% | 0.28% | 0.22% | 0.08% | 0.09% | 0.07% | 68.69% | 31.31% | 100.00% |
| 4th Congress | 52.09% | 47.91% | 57.79% | 42.21% | 42.07% | 24.90% | 16.58% | 13.07% | 0.80% | 1.25% | 0.47% | 0.43% | 0.10% | 0.23% | 0.09% | 67.47% | 32.53% | 100.00% |
| 5th Congress | 55.85% | 44.15% | 59.86% | 40.14% | 37.57% | 20.04% | 29.23% | 11.34% | 0.37% | 0.67% | 0.34% | 0.22% | 0.09% | 0.08% | 0.05% | 73.78% | 26.22% | 100.00% |
| 6th Congress | 47.93% | 52.07% | 57.53% | 42.47% | 33.27% | 25.17% | 29.61% | 10.10% | 0.51% | 0.56% | 0.30% | 0.19% | 0.11% | 0.10% | 0.08% | 69.57% | 30.43% | 100.00% |
| 7th Congress | 58.22% | 41.78% | 63.17% | 36.83% | 30.86% | 20.00% | 33.63% | 13.01% | 0.82% | 0.68% | 0.38% | 0.25% | 0.11% | 0.16% | 0.11% | 73.83% | 26.17% | 100.00% |
| 8th Congress | 50.81% | 49.19% | 59.46% | 40.54% | 43.29% | 25.23% | 20.34% | 9.15% | 0.50% | 0.62% | 0.33% | 0.20% | 0.13% | 0.12% | 0.08% | 69.07% | 30.93% | 100.00% |
| 9th Congress | 57.48% | 42.52% | 66.23% | 33.77% | 34.22% | 21.53% | 31.42% | 11.05% | 0.39% | 0.64% | 0.29% | 0.20% | 0.10% | 0.09% | 0.06% | 75.44% | 24.56% | 100.00% |
| 10th Congress | 56.21% | 43.79% | 63.25% | 36.75% | 35.20% | 23.84% | 28.12% | 10.82% | 0.49% | 0.67% | 0.31% | 0.23% | 0.12% | 0.12% | 0.07% | 75.37% | 24.63% | 100.00% |
| 11th Congress | 48.00% | 52.00% | 54.99% | 45.01% | 39.58% | 26.12% | 22.64% | 9.59% | 0.64% | 0.57% | 0.30% | 0.21% | 0.14% | 0.10% | 0.10% | 68.21% | 31.79% | 100.00% |
| 12th Congress | 52.24% | 47.76% | 53.25% | 46.75% | 44.14% | 36.37% | 10.22% | 6.83% | 0.91% | 0.66% | 0.29% | 0.22% | 0.22% | 0.07% | 0.06% | 70.95% | 29.05% | 100.00% |
| 13th Congress | 53.71% | 46.29% | 67.93% | 32.07% | 37.64% | 36.56% | 15.02% | 7.86% | 1.06% | 0.82% | 0.37% | 0.26% | 0.23% | 0.10% | 0.07% | 71.91% | 28.09% | 100.00% |
| 14th Congress | 48.76% | 51.24% | 59.60% | 40.40% | 38.86% | 27.00% | 22.20% | 9.79% | 0.63% | 0.60% | 0.37% | 0.19% | 0.16% | 0.11% | 0.08% | 65.90% | 34.10% | 100.00% |
| 15th Congress | 50.82% | 49.18% | 59.83% | 40.17% | 42.13% | 36.80% | 10.97% | 6.62% | 1.25% | 1.04% | 0.32% | 0.32% | 0.37% | 0.10% | 0.08% | 70.58% | 29.42% | 100.00% |
| 16th Congress | 51.68% | 48.32% | 54.38% | 45.62% | 38.98% | 34.73% | 15.90% | 7.25% | 1.03% | 1.02% | 0.35% | 0.27% | 0.24% | 0.11% | 0.11% | 69.25% | 30.75% | 100.00% |
| 17th Congress | 51.29% | 48.71% | 55.75% | 44.25% | 36.15% | 36.01% | 16.94% | 7.69% | 1.11% | 1.02% | 0.33% | 0.23% | 0.30% | 0.13% | 0.10% | 69.81% | 30.19% | 100.00% |
| 18th Congress | 53.51% | 46.49% | 62.55% | 37.45% | 32.89% | 39.58% | 17.17% | 7.64% | 0.90% | 0.91% | 0.27% | 0.25% | 0.20% | 0.11% | 0.07% | 73.97% | 26.03% | 100.00% |
| Statewide | 51.53% | 48.47% | 59.16% | 40.84% | 38.80% | 30.23% | 19.74% | 8.74% | 0.79% | 0.77% | 0.33% | 0.24% | 0.19% | 0.11% | 0.08% | 70.57% | 29.43% | 100.00% |
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