| | Porter, WI | Sun Prairie, WI | United States |
| Population | 984 | 35,528 | 329,725,481 |
| Female Population | 49.7% | 51.1% | 50.5% |
| Male Population | 50.3% | 48.9% | 49.5% |
| Median Age | 46 | 37.6 | 38.4 |
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| Population - 2010 | 944 | 29,627 | 309,327,143 |
| Population - 2000 | 925 | 20,369 | 285,036,114 |
| Population - 1990 | 953 | 15,333 | 251,960,433 |
| Pop. 2000 to Now | 8.1% | 72.4% | 15.6% |
| Pop. 1990 to Now | 4.9% | 129.0% | 30.8% |
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| Population Density | 27.4 | 2,891.5 | 93.4 |
| Land Area | 35.9 | 12.3 | 3,531,905.4 |
| Water Area | 0.5 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Porter, WI | Sun Prairie, WI | United States |
| Age 0 to 4 | 9.9% | 6.2% | 5.9% |
| Age 5 to 9 | 1.9% | 6.4% | 6.1% |
| Age 10 to 14 | 6.9% | 7.1% | 6.6% |
| Age 15 to 17 | 2.1% | 5.1% | 3.9% |
| Age 18 to 20 | 1.2% | 3.1% | 4.0% |
| Age 21 to 24 | 3.3% | 4.0% | 5.2% |
| Age 25 to 34 | 10.3% | 13.6% | 13.8% |
| Age 35 to 44 | 13.9% | 16.6% | 12.9% |
| Age 45 to 54 | 10.0% | 12.1% | 12.6% |
| Age 55 to 59 | 10.2% | 6.7% | 6.7% |
| Age 60 to 64 | 9.2% | 5.1% | 6.3% |
| Age 65 to 74 | 14.3% | 7.8% | 9.6% |
| Age 75 to 84 | 4.7% | 3.8% | 4.5% |
| Age 85 and over | 2.1% | 2.3% | 1.9% |
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| Race | | | |
| | Porter, WI | Sun Prairie, WI | United States |
| White | 98.7% | 78.2% | 59.4% |
| Black | 0.4% | 7.5% | 12.2% |
| Asian | 0.0% | 5.9% | 5.6% |
| Native American | 0.2% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.2% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 0.6% | 4.2% | 3.2% |
| Hispanic | 0.1% | 3.7% | 18.4% |
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| Marriage & Family | | | |
| | Porter, WI | Sun Prairie, WI | United States |
| Married Population | 60.3% | 52.5% | 49.8% |
| Currently Married | 60.3% | 51.7% | 48.0% |
| Married but Separated | 0.0% | 0.8% | 1.8% |
| Single Population | 39.8% | 47.5% | 50.2% |
| Never Married | 18.3% | 30.6% | 33.8% |
| Divorced | 11.0% | 12.0% | 10.8% |
| Widowed | 10.5% | 4.9% | 5.6% |
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| Household Size | 2.41 | 2.41 | 2.60 |
| Households | 409 | 14,701 | 124,010,992 |
| Family Households | 285 | 9,037 | 80,755,759 |
| Married couple, w/children | 24.2% | 35.5% | 30.5% |
| Married couple, no children | 56.1% | 45.2% | 42.9% |
| Non Family Households | 124 | 5,664 | 43,255,233 |
| Single householder, w/children | 13.7% | 12.9% | 15.8% |
| Single householder, no children | 6.0% | 6.3% | 10.8% |