Census data for Sundby parish
| 1880 | 0 | 0 | 0 | 0.00% | 0 | 0.00% | 0 | 0.00% | |
| 1885 | 1,093 | 8,389 | 4,120 | 49.11% | 4,265 | 50.84% | 4 | 0.05% | 7,495 |
| 1890 | 27 | 294 | 144 | 48.98% | 123 | 41.84% | 27 | 9.18% | |
| 1895 | 1,931 | 9,431 | 4,352 | 46.15% | 4,247 | 45.03% | 832 | 8.82% | |
| 1901 | 2,437 | 10,330 | 5,101 | 49.38% | 5,219 | 50.52% | 10 | 0.10% | 9,883 |
| 1906 | 5,293 | 100 | 52 | 52.00% | 48 | 48.00% | 0 | 0.00% | 0 |
| 1911 | 6,174 | 69 | 29 | 42.03% | 30 | 43.48% | 10 | 14.49% | |
| 1916 | 13,948 | 40 | 9 | 22.50% | 31 | 77.50% | 0 | 0.00% | 0 |
| 1921 | 6,335 | 110 | 42 | 38.18% | 54 | 49.09% | 14 | 12.73% | 0 |
| 1925 | 36,756 | 71 | 30 | 42.25% | 26 | 36.62% | 15 | 21.13% | 0 |
| 1930 | 35,969 | 954 | 474 | 49.69% | 477 | 50.00% | 3 | 0.31% | 926 |
| 1940 | 48,017 | 107 | 49 | 45.79% | 57 | 53.27% | 1 | 0.93% | 0 |