Age distribution of patients in mid June 1994
| Age group | No resident | No with US | Prevalence | Prevalence of all US per 100 000 | Prevalence of US 1 and 2 per 100 000 |
| 15–29 | 233 329 | 12 | 1 in 19 444 | 5.1 | 5.1 |
| 30–49 | 264 351 | 25 (21) | 1 in 10 574 | 9.5 | 7.9 |
| 50–69 | 183 747 | 9 (6) | 1 in 20 416 | 4.9 | 3.3 |
| 70–85+ | 106 719 | 3 | 1 in 35 573 | 2.8 | 2.8 |
| Total | 788 146 | 49 | 1 in 16 085 | 6.2 | 5.3 |
↵Numbers in parentheses refer to patients with Usher syndromes 1 and 2 (where this is different from the total).