| | Andover, NY | Olean, NY | United States |
| Population | 1,629 | 13,941 | 329,725,481 |
| Female Population | 47.2% | 50.7% | 50.5% |
| Male Population | 52.8% | 49.3% | 49.5% |
| Median Age | 48.1 | 38.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,834 | 14,404 | 309,327,143 |
| Population - 2000 | 1,945 | 15,347 | 285,036,114 |
| Population - 1990 | 1,981 | 16,946 | 251,960,433 |
| Pop. 2000 to Now | -12.4% | -12.9% | 15.6% |
| Pop. 1990 to Now | -14.0% | -21.1% | 30.8% |
| space4 | | | |
| Population Density | 41.3 | 2,362.9 | 93.4 |
| Land Area | 39.4 | 5.9 | 3,531,905.4 |
| Water Area | 0.1 | 0.3 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Andover, NY | Olean, NY | United States |
| Age 0 to 4 | 5.6% | 5.9% | 5.9% |
| Age 5 to 9 | 5.2% | 6.9% | 6.1% |
| Age 10 to 14 | 6.3% | 7.5% | 6.6% |
| Age 15 to 17 | 4.6% | 4.0% | 3.9% |
| Age 18 to 20 | 1.2% | 2.1% | 4.0% |
| Age 21 to 24 | 2.1% | 5.4% | 5.2% |
| Age 25 to 34 | 12.2% | 12.6% | 13.8% |
| Age 35 to 44 | 8.6% | 13.8% | 12.9% |
| Age 45 to 54 | 14.3% | 11.6% | 12.6% |
| Age 55 to 59 | 11.8% | 5.8% | 6.7% |
| Age 60 to 64 | 9.0% | 7.6% | 6.3% |
| Age 65 to 74 | 11.7% | 10.3% | 9.6% |
| Age 75 to 84 | 4.9% | 4.3% | 4.5% |
| Age 85 and over | 2.5% | 2.2% | 1.9% |
| space1 | | | |
| Race | | | |
| | Andover, NY | Olean, NY | United States |
| White | 98.3% | 88.2% | 59.4% |
| Black | 0.0% | 2.3% | 12.2% |
| Asian | 0.0% | 2.2% | 5.6% |
| Native American | 0.0% | 1.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.4% | 0.2% | 0.4% |
| Two or More Races | 0.6% | 4.9% | 3.2% |
| Hispanic | 0.7% | 1.3% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Andover, NY | Olean, NY | United States |
| Married Population | 52.0% | 40.9% | 49.8% |
| Currently Married | 49.9% | 37.4% | 48.0% |
| Married but Separated | 2.1% | 3.5% | 1.8% |
| Single Population | 48.0% | 59.1% | 50.2% |
| Never Married | 30.1% | 36.1% | 33.8% |
| Divorced | 10.4% | 14.5% | 10.8% |
| Widowed | 7.5% | 8.4% | 5.6% |
| space5 | | | |
| Household Size | 2.48 | 2.24 | 2.60 |
| Households | 658 | 6,115 | 124,010,992 |
| Family Households | 424 | 3,204 | 80,755,759 |
| Married couple, w/children | 22.6% | 32.0% | 30.5% |
| Married couple, no children | 53.5% | 28.8% | 42.9% |
| Non Family Households | 234 | 2,911 | 43,255,233 |
| Single householder, w/children | 18.4% | 23.7% | 15.8% |
| Single householder, no children | 5.4% | 15.5% | 10.8% |