| | St. Andrews, SC | South Hill, WA | United States |
| Population | 21,383 | 66,713 | 329,725,481 |
| Female Population | 53.4% | 49.8% | 50.5% |
| Male Population | 46.7% | 50.2% | 49.5% |
| Median Age | 32.5 | 34.3 | 38.4 |
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| Population - 2010 | 20,835 | 52,476 | 309,327,143 |
| Population - 2000 | 21,814 | 31,623 | 285,036,114 |
| Population - 1990 | 25,692 | 12,963 | 251,960,433 |
| Pop. 2000 to Now | 3.9% | 93.0% | 15.6% |
| Pop. 1990 to Now | -11.8% | 370.8% | 30.8% |
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| Population Density | 3,452.8 | 3,634.2 | 93.4 |
| Land Area | 6.2 | 18.4 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | St. Andrews, SC | South Hill, WA | United States |
| Age 0 to 4 | 6.9% | 6.9% | 5.9% |
| Age 5 to 9 | 6.2% | 7.8% | 6.1% |
| Age 10 to 14 | 4.9% | 8.2% | 6.6% |
| Age 15 to 17 | 2.6% | 5.5% | 3.9% |
| Age 18 to 20 | 3.9% | 4.1% | 4.0% |
| Age 21 to 24 | 8.9% | 4.5% | 5.2% |
| Age 25 to 34 | 20.1% | 14.2% | 13.8% |
| Age 35 to 44 | 13.7% | 15.4% | 12.9% |
| Age 45 to 54 | 10.5% | 12.2% | 12.6% |
| Age 55 to 59 | 6.1% | 6.0% | 6.7% |
| Age 60 to 64 | 4.6% | 5.0% | 6.3% |
| Age 65 to 74 | 7.7% | 6.4% | 9.6% |
| Age 75 to 84 | 2.7% | 2.5% | 4.5% |
| Age 85 and over | 1.1% | 1.2% | 1.9% |
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| Race | | | |
| | St. Andrews, SC | South Hill, WA | United States |
| White | 22.1% | 66.2% | 59.4% |
| Black | 66.5% | 4.1% | 12.2% |
| Asian | 2.1% | 6.3% | 5.6% |
| Native American | 0.1% | 0.4% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.9% | 0.2% |
| Other | 0.6% | 0.2% | 0.4% |
| Two or More Races | 4.6% | 9.9% | 3.2% |
| Hispanic | 4.1% | 12.0% | 18.4% |
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| Marriage & Family | | | |
| | St. Andrews, SC | South Hill, WA | United States |
| Married Population | 31.0% | 55.2% | 49.8% |
| Currently Married | 27.2% | 53.8% | 48.0% |
| Married but Separated | 3.8% | 1.5% | 1.8% |
| Single Population | 69.0% | 44.8% | 50.2% |
| Never Married | 49.2% | 30.6% | 33.8% |
| Divorced | 15.3% | 10.2% | 10.8% |
| Widowed | 4.5% | 3.9% | 5.6% |
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| Household Size | 2.10 | 3.06 | 2.60 |
| Households | 10,111 | 21,770 | 124,010,992 |
| Family Households | 4,746 | 17,527 | 80,755,759 |
| Married couple, w/children | 21.5% | 37.3% | 30.5% |
| Married couple, no children | 26.3% | 36.7% | 42.9% |
| Non Family Households | 5,365 | 4,243 | 43,255,233 |
| Single householder, w/children | 32.7% | 17.8% | 15.8% |
| Single householder, no children | 19.5% | 8.2% | 10.8% |