| PEOPLE | Sidney | Decatur | United States |
| Population | 21,229 | 9,405 | 308,035,306 |
| Pop. Density | 1,766 | 1,628 | 87 |
| Pop. Change | 3.07% | -3.48% | 8.07% |
| Median Age | 36.1 | 37.1 | 37.3 |
| Households | 8,344 | 4,011 | 116,716,292 |
| Household Size | 2.52 | 2.36 | 2.58 |
| Male Population | 49.09% | 48.41% | 49.27% |
| Female Population | 50.91% | 51.59% | 50.96% |
| Married Population | 52.03% | 53.93% | 47.02% |
| Single Population | 47.97% | 46.07% | 52.98% |
| ESTIMATED TOTAL POPULATION BY AGE | | | |
| Age 0 to 4 | 8.12% | 7.40% | 6.56% |
| Age 5 to 9 | 7.62% | 6.78% | 6.61% |
| Age 10 to 14 | 7.18% | 6.43% | 6.71% |
| Age 15 to 17 | 4.27% | 4.09% | 4.21% |
| Age 18 to 20 | 2.71% | 2.73% | 2.95% |
| Age 21 to 24 | 5.91% | 6.71% | 7.01% |
| Age 25 to 34 | 12.86% | 13.34% | 13.33% |
| Age 35 to 44 | 12.75% | 12.17% | 13.33% |
| Age 45 to 49 | 14.15% | 13.55% | 14.61% |
| Age 50 to 54 | 14.15% | 13.55% | 14.61% |
| Age 55 to 59 | 12.05% | 12.17% | 11.84% |
| Age 60 to 64 | 12.05% | 12.17% | 11.84% |
| Age 65 to 74 | 6.76% | 6.87% | 7.05% |
| Age 75 to 84 | 4.21% | 5.24% | 4.24% |
| Age 85 and over | 1.43% | 2.50% | 1.78% |
| RACE | | | |
| White | 90.28% | 94.72% | 72.41% |
| Black | 3.66% | 0.54% | 12.61% |
| Asian | 1.65% | 0.36% | 4.75% |
| American Indian | 0.20% | 0.37% | 0.95% |
| Other | 4.21% | 4.01% | 9.28% |
| Hispanic | 0.96% | 0.51% | 16.35% |
| Non-Hispanic | 99.04% | 99.49% | 83.65% |
| FAMILY | | | |
| Married, w/children | 26.75% | 26.24% | 30.42% |
| Married, no children | 41.58% | 43.53% | 42.46% |
| Single, w/children | 20.44% | 19.63% | 14.39% |
| Single, no children | 11.22% | 10.59% | 12.73% |
| Divorced | 14.69% | 13.72% | 10.62% |
| Separated | 4.64% | 2.67% | 4.97% |
| Widowed | 6.89% | 7.76% | 6.14% |
| Now Married | 51.04% | 52.87% | 46.32% |
| Never Married | 22.74% | 22.97% | 31.95% |
