| | Bellevue, IA | El Cajon, CA | United States |
| Population | 2,345 | 106,043 | 329,725,481 |
| Female Population | 54.8% | 50.8% | 50.5% |
| Male Population | 45.2% | 49.3% | 49.5% |
| Median Age | 41.9 | 34.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,205 | 99,815 | 309,327,143 |
| Population - 2000 | 2,350 | 94,869 | 285,036,114 |
| Population - 1990 | 2,239 | 88,693 | 251,960,433 |
| Pop. 2000 to Now | -7.0% | 7.9% | 15.6% |
| Pop. 1990 to Now | -2.4% | 15.5% | 30.8% |
| space4 | | | |
| Population Density | 1,690.7 | 7,320.9 | 93.4 |
| Land Area | 1.4 | 14.5 | 3,531,905.4 |
| Water Area | 0.1 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Bellevue, IA | El Cajon, CA | United States |
| Age 0 to 4 | 9.9% | 7.2% | 5.9% |
| Age 5 to 9 | 4.5% | 6.6% | 6.1% |
| Age 10 to 14 | 6.3% | 7.4% | 6.6% |
| Age 15 to 17 | 3.8% | 4.2% | 3.9% |
| Age 18 to 20 | 3.6% | 3.9% | 4.0% |
| Age 21 to 24 | 3.7% | 5.3% | 5.2% |
| Age 25 to 34 | 11.6% | 15.7% | 13.8% |
| Age 35 to 44 | 9.7% | 14.0% | 12.9% |
| Age 45 to 54 | 10.0% | 10.9% | 12.6% |
| Age 55 to 59 | 8.7% | 5.8% | 6.7% |
| Age 60 to 64 | 5.9% | 6.2% | 6.3% |
| Age 65 to 74 | 11.2% | 7.9% | 9.6% |
| Age 75 to 84 | 6.6% | 3.4% | 4.5% |
| Age 85 and over | 4.6% | 1.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Bellevue, IA | El Cajon, CA | United States |
| White | 97.5% | 56.7% | 59.4% |
| Black | 0.0% | 6.2% | 12.2% |
| Asian | 0.2% | 4.3% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.5% | 0.2% |
| Other | 0.0% | 0.4% | 0.4% |
| Two or More Races | 2.3% | 4.7% | 3.2% |
| Hispanic | 0.0% | 27.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Bellevue, IA | El Cajon, CA | United States |
| Married Population | 57.6% | 46.3% | 49.8% |
| Currently Married | 56.3% | 43.9% | 48.0% |
| Married but Separated | 1.3% | 2.4% | 1.8% |
| Single Population | 42.4% | 53.7% | 50.2% |
| Never Married | 23.4% | 37.6% | 33.8% |
| Divorced | 7.5% | 10.5% | 10.8% |
| Widowed | 11.4% | 5.7% | 5.6% |
| space5 | | | |
| Household Size | 2.42 | 2.96 | 2.60 |
| Households | 944 | 35,003 | 124,010,992 |
| Family Households | 608 | 25,018 | 80,755,759 |
| Married couple, w/children | 38.7% | 34.1% | 30.5% |
| Married couple, no children | 44.9% | 30.9% | 42.9% |
| Non Family Households | 336 | 9,985 | 43,255,233 |
| Single householder, w/children | 10.2% | 20.4% | 15.8% |
| Single householder, no children | 6.3% | 14.6% | 10.8% |