| Census of 5th April | Great Britain | Ireland | United Kingdom | Ireland. Per cent of United Kingdom |
| 1821 | 14,091,757 | 6,801,827 | 20,893,584 | 32.5 |
| 1831 | 16,361,183 | 7,767,401 | 24,128,584 | 32.0 |
| 1841 | 18,534,332 | 8,175,124 | 26,709,456 | 31.0 |
| 1851 | 20,816,351 | 6,574,278 | 27,390,629 | 24.0 |
| 1861 | 23,128,518 | 5,798,967 | 28,927,485 | 20.0 |
| 1871 | 26,072,284 | 5,412,377 | 31,484,661 | 17.0 |
| 1881 | 29,710,012 | 5,174,836 | 34,884,848 | 15.0 |
| 1891 | 33,028,172 | 4,704,750 | 37,732,922 | 12.5 |
| --- | --- | --- | --- | --- |
| 1899 | 36,024,438 | 4,535,516 | 40,559,954 | 11.2 |
| 1900 * | 36,683,879 | 4,466,326 | 41,150,205 | 10.85 |
| 1901 | 37,103,328 | 4,443,370 | 41,546,698 | 10.69 |
| 1902 | 37,528,925 | 4,432,287 | 41,961,212 | 10.56 |
| 1903 | 37,957,561 | 4,414,995 | 42,372,556 | 10.42 |
| 1904 | 38,391,090 | 4,398,462 | 42,789,552 | 10.28 |
| 1905 | 38,829,580 | 4,388,107 | 43,217,687 | 10.15 |