| | Leetsdale, PA | Sammamish, WA | United States |
| Population | 1,137 | 66,532 | 329,725,481 |
| Female Population | 48.6% | 51.8% | 50.5% |
| Male Population | 51.5% | 48.2% | 49.5% |
| Median Age | 44.6 | 39.2 | 38.4 |
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| Population - 2010 | 1,203 | 57,656 | 309,327,143 |
| Population - 2000 | 1,232 | 34,104 | 285,036,114 |
| Population - 1990 | 1,387 | 23,294 | 251,960,433 |
| Pop. 2000 to Now | -6.7% | 93.4% | 15.6% |
| Pop. 1990 to Now | -17.2% | 183.2% | 30.8% |
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| Population Density | 1,137.0 | 3,255.5 | 93.4 |
| Land Area | 1.0 | 20.4 | 3,531,905.4 |
| Water Area | 0.2 | 3.7 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Leetsdale, PA | Sammamish, WA | United States |
| Age 0 to 4 | 3.1% | 6.1% | 5.9% |
| Age 5 to 9 | 7.8% | 7.3% | 6.1% |
| Age 10 to 14 | 4.5% | 9.9% | 6.6% |
| Age 15 to 17 | 3.8% | 6.3% | 3.9% |
| Age 18 to 20 | 2.6% | 2.7% | 4.0% |
| Age 21 to 24 | 3.2% | 2.9% | 5.2% |
| Age 25 to 34 | 10.7% | 8.0% | 13.8% |
| Age 35 to 44 | 15.5% | 18.2% | 12.9% |
| Age 45 to 54 | 14.2% | 19.1% | 12.6% |
| Age 55 to 59 | 3.2% | 6.5% | 6.7% |
| Age 60 to 64 | 8.0% | 5.3% | 6.3% |
| Age 65 to 74 | 15.6% | 5.6% | 9.6% |
| Age 75 to 84 | 7.2% | 1.7% | 4.5% |
| Age 85 and over | 0.6% | 0.5% | 1.9% |
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| Race | | | |
| | Leetsdale, PA | Sammamish, WA | United States |
| White | 81.7% | 55.8% | 59.4% |
| Black | 3.6% | 1.6% | 12.2% |
| Asian | 4.9% | 33.3% | 5.6% |
| Native American | 0.0% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.3% | 0.4% | 0.4% |
| Two or More Races | 7.7% | 4.9% | 3.2% |
| Hispanic | 1.8% | 3.5% | 18.4% |
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| Marriage & Family | | | |
| | Leetsdale, PA | Sammamish, WA | United States |
| Married Population | 46.8% | 70.7% | 49.8% |
| Currently Married | 44.3% | 70.0% | 48.0% |
| Married but Separated | 2.5% | 0.7% | 1.8% |
| Single Population | 53.2% | 29.3% | 50.2% |
| Never Married | 30.5% | 22.7% | 33.8% |
| Divorced | 15.5% | 4.8% | 10.8% |
| Widowed | 7.3% | 1.9% | 5.6% |
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| Household Size | 2.04 | 3.03 | 2.60 |
| Households | 558 | 21,930 | 124,010,992 |
| Family Households | 300 | 19,138 | 80,755,759 |
| Married couple, w/children | 28.0% | 54.5% | 30.5% |
| Married couple, no children | 39.7% | 34.7% | 42.9% |
| Non Family Households | 258 | 2,792 | 43,255,233 |
| Single householder, w/children | 19.3% | 7.1% | 15.8% |
| Single householder, no children | 13.0% | 3.7% | 10.8% |