| Date | Population | Change | % Change |
| 1900 | 32,438 | - | - |
| 1910 | 33,913 | 1,475 | 0.4 |
| 1920 | 35,813 | 1,900 | 0.5 |
| 1930 | 34,664 | -1,149 | -0.3 |
| 1940 | 33,336 | -1,328 | -0.4 |
| 1950 | 31,577 | -1,759 | -0.5 |
| 1960 | 35,120 | 3,543 | 1.1 |
| 1970 | 34,137 | -983 | -0.3 |
| 1980 | 36,378 | 2,241 | 0.6 |
| 1990 | 35,437 | -941 | -0.3 |
| 2000 | 39,403 | 3,966 | 1.1 |