| Value | Category | Cases | |
|---|---|---|---|
| 1 | before 1945 | 11 |
5.1%
|
| 2 | 1945-1960 | 17 |
7.9%
|
| 3 | 1961-1980 | 86 |
39.8%
|
| 4 | 1981-1990 | 64 |
29.6%
|
| 5 | after 1990 | 38 |
17.6%
|