Census data for Sundby parish
| 1880 | 0 | 0 | 0 | 0.00% | 0 | 0.00% | 0 | 0.00% | |
| 1885 | 1,093 | 8,389 | 4,117 | 49.08% | 4,268 | 50.88% | 4 | 0.05% | 7,215 |
| 1890 | 27 | 294 | 146 | 49.66% | 126 | 42.86% | 22 | 7.48% | 0 |
| 1895 | 1,931 | 9,495 | 4,511 | 47.51% | 4,502 | 47.41% | 482 | 5.08% | |
| 1901 | 3,016 | 16,727 | 8,239 | 49.26% | 8,485 | 50.73% | 3 | 0.02% | 0 |
| 1906 | 5,293 | 159 | 80 | 50.31% | 78 | 49.06% | 1 | 0.63% | 0 |
| 1911 | 6,174 | 88 | 44 | 50.00% | 36 | 40.91% | 8 | 9.09% | 0 |
| 1916 | 13,948 | 48 | 16 | 33.33% | 32 | 66.67% | 0 | 0.00% | 0 |
| 1921 | 6,335 | 145 | 61 | 42.07% | 74 | 51.03% | 10 | 6.90% | 0 |
| 1925 | 36,756 | 76 | 39 | 51.32% | 30 | 39.47% | 7 | 9.21% | 0 |
| 1930 | 35,969 | 975 | 486 | 49.85% | 488 | 50.05% | 1 | 0.10% | 267 |
| 1940 | 48,017 | 124 | 58 | 46.77% | 66 | 53.23% | 0 | 0.00% | 0 |