Version July 2025
| Country | Incidence | Reference |
| Finland | 9.2/100,000 | Laaksonen, 1966 |
| Finland | 19.6/100,000 | Kunnamo, 1986 |
| Finland | 31.7/100,000 | Uusitupa, 2024 |
| Sweden | 10.9/100,000 | Gare, 1992 |
| Canada | 5.3/100,000 | Oen, 1995 |
| United Kingdom | 10.0/100,000 | Symmons, 1996 |
