| PEOPLE | Janesville | Markham | United States |
| Population | 63,575 | 12,508 | 308,035,306 |
| Pop. Density | 1,878 | 2,356 | 87 |
| Pop. Change | 2.90% | -2.16% | 8.07% |
| Median Age | 37.1 | 34.1 | 37.3 |
| Households | 25,828 | 3,978 | 116,716,292 |
| Household Size | 2.42 | 3.15 | 2.58 |
| Male Population | 48.92% | 46.64% | 49.27% |
| Female Population | 51.08% | 53.36% | 50.96% |
| Married Population | 49.34% | 32.63% | 47.02% |
| Single Population | 50.66% | 67.37% | 52.98% |
| ESTIMATED TOTAL POPULATION BY AGE | | | |
| Age 0 to 4 | 6.69% | 6.55% | 6.56% |
| Age 5 to 9 | 6.85% | 7.94% | 6.61% |
| Age 10 to 14 | 6.93% | 8.75% | 6.71% |
| Age 15 to 17 | 4.28% | 6.23% | 4.21% |
| Age 18 to 20 | 2.40% | 3.60% | 2.95% |
| Age 21 to 24 | 5.99% | 6.42% | 7.01% |
| Age 25 to 34 | 14.05% | 11.62% | 13.33% |
| Age 35 to 44 | 13.81% | 12.66% | 13.33% |
| Age 45 to 49 | 14.22% | 13.05% | 14.61% |
| Age 50 to 54 | 14.22% | 13.05% | 14.61% |
| Age 55 to 59 | 10.89% | 10.60% | 11.84% |
| Age 60 to 64 | 10.89% | 10.60% | 11.84% |
| Age 65 to 74 | 7.18% | 6.78% | 7.05% |
| Age 75 to 84 | 4.84% | 4.38% | 4.24% |
| Age 85 and over | 1.87% | 1.42% | 1.78% |
| RACE | | | |
| White | 91.70% | 12.74% | 72.41% |
| Black | 2.57% | 80.98% | 12.61% |
| Asian | 1.35% | 0.68% | 4.75% |
| American Indian | 0.29% | 0.21% | 0.95% |
| Other | 4.09% | 5.39% | 9.28% |
| Hispanic | 0.56% | 0.74% | 16.35% |
| Non-Hispanic | 99.44% | 99.26% | 83.65% |
| FAMILY | | | |
| Married, w/children | 28.56% | 18.23% | 30.42% |
| Married, no children | 43.41% | 28.94% | 42.46% |
| Single, w/children | 18.33% | 23.70% | 14.39% |
| Single, no children | 9.70% | 29.13% | 12.73% |
| Divorced | 14.28% | 10.84% | 10.62% |
| Separated | 2.08% | 7.32% | 4.97% |
| Widowed | 5.80% | 7.88% | 6.14% |
| Now Married | 49.72% | 32.77% | 46.32% |
| Never Married | 28.12% | 41.19% | 31.95% |
