| | St. John, WA | Endicott, WA | United States |
| Population | 608 | 400 | 329,725,481 |
| Female Population | 53.6% | 46.0% | 50.5% |
| Male Population | 46.4% | 54.0% | 49.5% |
| Median Age | 55.2 | 42.3 | 38.4 |
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| Population - 2010 | 543 | 299 | 309,327,143 |
| Population - 2000 | 548 | 621 | 285,036,114 |
| Population - 1990 | 499 | 320 | 251,960,433 |
| Pop. 2000 to Now | -0.2% | -52.5% | 15.6% |
| Pop. 1990 to Now | 9.6% | -7.8% | 30.8% |
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| Population Density | 906.1 | 1,346.8 | 93.4 |
| Land Area | 0.7 | 0.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | St. John, WA | Endicott, WA | United States |
| Age 0 to 4 | 5.6% | 0.0% | 5.9% |
| Age 5 to 9 | 4.1% | 10.3% | 6.1% |
| Age 10 to 14 | 8.7% | 11.3% | 6.6% |
| Age 15 to 17 | 4.8% | 10.8% | 3.9% |
| Age 18 to 20 | 0.7% | 3.5% | 4.0% |
| Age 21 to 24 | 0.0% | 0.0% | 5.2% |
| Age 25 to 34 | 11.2% | 6.3% | 13.8% |
| Age 35 to 44 | 8.7% | 19.8% | 12.9% |
| Age 45 to 54 | 4.6% | 4.8% | 12.6% |
| Age 55 to 59 | 13.0% | 6.5% | 6.7% |
| Age 60 to 64 | 9.0% | 15.0% | 6.3% |
| Age 65 to 74 | 13.8% | 4.8% | 9.6% |
| Age 75 to 84 | 12.3% | 7.0% | 4.5% |
| Age 85 and over | 3.5% | 0.3% | 1.9% |
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| Race | | | |
| | St. John, WA | Endicott, WA | United States |
| White | 90.8% | 96.0% | 59.4% |
| Black | 4.4% | 0.5% | 12.2% |
| Asian | 0.2% | 0.0% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.0% | 3.5% | 3.2% |
| Hispanic | 3.6% | 0.0% | 18.4% |
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| Marriage & Family | | | |
| | St. John, WA | Endicott, WA | United States |
| Married Population | 55.8% | 50.3% | 49.8% |
| Currently Married | 55.4% | 44.3% | 48.0% |
| Married but Separated | 0.4% | 6.1% | 1.8% |
| Single Population | 44.2% | 49.7% | 50.2% |
| Never Married | 16.7% | 27.7% | 33.8% |
| Divorced | 20.2% | 17.8% | 10.8% |
| Widowed | 7.3% | 4.1% | 5.6% |
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| Household Size | 2.66 | 2.60 | 2.60 |
| Households | 229 | 154 | 124,010,992 |
| Family Households | 149 | 97 | 80,755,759 |
| Married couple, w/children | 32.2% | 34.0% | 30.5% |
| Married couple, no children | 58.4% | 35.1% | 42.9% |
| Non Family Households | 80 | 57 | 43,255,233 |
| Single householder, w/children | 6.0% | 21.6% | 15.8% |
| Single householder, no children | 3.4% | 9.3% | 10.8% |