| | Lafayette, OR | Dallas, OR | United States |
| Population | 4,369 | 16,663 | 329,725,481 |
| Female Population | 45.7% | 52.8% | 50.5% |
| Male Population | 54.3% | 47.2% | 49.5% |
| Median Age | 35.7 | 42.3 | 38.4 |
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| Population - 2010 | 3,742 | 14,618 | 309,327,143 |
| Population - 2000 | 2,586 | 12,459 | 285,036,114 |
| Population - 1990 | 1,292 | 9,422 | 251,960,433 |
| Pop. 2000 to Now | 64.7% | 39.1% | 15.6% |
| Pop. 1990 to Now | 229.6% | 83.9% | 30.8% |
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| Population Density | 5,050.9 | 3,393.0 | 93.4 |
| Land Area | 0.9 | 4.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Lafayette, OR | Dallas, OR | United States |
| Age 0 to 4 | 7.6% | 6.3% | 5.9% |
| Age 5 to 9 | 6.7% | 4.0% | 6.1% |
| Age 10 to 14 | 6.5% | 5.5% | 6.6% |
| Age 15 to 17 | 3.4% | 3.2% | 3.9% |
| Age 18 to 20 | 3.6% | 5.0% | 4.0% |
| Age 21 to 24 | 4.7% | 8.2% | 5.2% |
| Age 25 to 34 | 16.5% | 11.7% | 13.8% |
| Age 35 to 44 | 14.6% | 9.4% | 12.9% |
| Age 45 to 54 | 13.4% | 11.0% | 12.6% |
| Age 55 to 59 | 7.4% | 5.4% | 6.7% |
| Age 60 to 64 | 6.5% | 6.7% | 6.3% |
| Age 65 to 74 | 6.6% | 14.0% | 9.6% |
| Age 75 to 84 | 2.2% | 6.3% | 4.5% |
| Age 85 and over | 0.3% | 3.4% | 1.9% |
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| Race | | | |
| | Lafayette, OR | Dallas, OR | United States |
| White | 71.1% | 87.2% | 59.4% |
| Black | 0.0% | 0.9% | 12.2% |
| Asian | 0.3% | 0.2% | 5.6% |
| Native American | 3.6% | 1.5% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.4% | 1.4% | 0.4% |
| Two or More Races | 2.9% | 3.3% | 3.2% |
| Hispanic | 21.6% | 5.4% | 18.4% |
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| Marriage & Family | | | |
| | Lafayette, OR | Dallas, OR | United States |
| Married Population | 59.3% | 52.2% | 49.8% |
| Currently Married | 56.2% | 51.3% | 48.0% |
| Married but Separated | 3.2% | 0.9% | 1.8% |
| Single Population | 40.7% | 47.8% | 50.2% |
| Never Married | 21.0% | 27.5% | 33.8% |
| Divorced | 18.1% | 14.1% | 10.8% |
| Widowed | 1.5% | 6.2% | 5.6% |
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| Household Size | 2.97 | 2.46 | 2.60 |
| Households | 1,473 | 6,612 | 124,010,992 |
| Family Households | 1,084 | 4,283 | 80,755,759 |
| Married couple, w/children | 49.3% | 29.2% | 30.5% |
| Married couple, no children | 36.9% | 50.9% | 42.9% |
| Non Family Households | 389 | 2,329 | 43,255,233 |
| Single householder, w/children | 9.9% | 11.6% | 15.8% |
| Single householder, no children | 4.0% | 8.3% | 10.8% |