| | Derby, KS | Delta, CO | United States |
| Population | 25,365 | 9,036 | 329,725,481 |
| Female Population | 50.6% | 49.5% | 50.5% |
| Male Population | 49.4% | 50.5% | 49.5% |
| Median Age | 35.6 | 44.9 | 38.4 |
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| Population - 2010 | 22,524 | 8,865 | 309,327,143 |
| Population - 2000 | 17,807 | 6,400 | 285,036,114 |
| Population - 1990 | 14,699 | 3,789 | 251,960,433 |
| Pop. 2000 to Now | 41.2% | 41.1% | 15.6% |
| Pop. 1990 to Now | 71.1% | 138.3% | 30.8% |
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| Population Density | 2,473.4 | 680.8 | 93.4 |
| Land Area | 10.3 | 13.3 | 3,531,905.4 |
| Water Area | 0.1 | 0.3 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Derby, KS | Delta, CO | United States |
| Age 0 to 4 | 5.5% | 3.7% | 5.9% |
| Age 5 to 9 | 8.3% | 7.1% | 6.1% |
| Age 10 to 14 | 9.1% | 6.8% | 6.6% |
| Age 15 to 17 | 4.2% | 3.7% | 3.9% |
| Age 18 to 20 | 3.3% | 3.9% | 4.0% |
| Age 21 to 24 | 5.2% | 5.7% | 5.2% |
| Age 25 to 34 | 12.9% | 8.0% | 13.8% |
| Age 35 to 44 | 14.6% | 11.3% | 12.9% |
| Age 45 to 54 | 10.1% | 13.0% | 12.6% |
| Age 55 to 59 | 7.1% | 5.4% | 6.7% |
| Age 60 to 64 | 4.9% | 8.8% | 6.3% |
| Age 65 to 74 | 7.7% | 13.3% | 9.6% |
| Age 75 to 84 | 5.1% | 5.6% | 4.5% |
| Age 85 and over | 2.0% | 3.8% | 1.9% |
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| Race | | | |
| | Derby, KS | Delta, CO | United States |
| White | 82.3% | 69.5% | 59.4% |
| Black | 1.2% | 0.3% | 12.2% |
| Asian | 1.3% | 2.4% | 5.6% |
| Native American | 0.7% | 0.9% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 5.7% | 2.0% | 3.2% |
| Hispanic | 8.7% | 24.8% | 18.4% |
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| Marriage & Family | | | |
| | Derby, KS | Delta, CO | United States |
| Married Population | 60.3% | 46.2% | 49.8% |
| Currently Married | 59.1% | 44.9% | 48.0% |
| Married but Separated | 1.1% | 1.3% | 1.8% |
| Single Population | 39.7% | 53.8% | 50.2% |
| Never Married | 23.4% | 26.8% | 33.8% |
| Divorced | 10.6% | 18.4% | 10.8% |
| Widowed | 5.8% | 8.6% | 5.6% |
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| Household Size | 2.54 | 2.60 | 2.60 |
| Households | 9,953 | 3,387 | 124,010,992 |
| Family Households | 6,783 | 2,025 | 80,755,759 |
| Married couple, w/children | 37.1% | 29.0% | 30.5% |
| Married couple, no children | 43.1% | 39.7% | 42.9% |
| Non Family Households | 3,170 | 1,362 | 43,255,233 |
| Single householder, w/children | 10.8% | 14.8% | 15.8% |
| Single householder, no children | 9.0% | 16.4% | 10.8% |