| Value | Category | Cases | |
|---|---|---|---|
| 1972 | 1 |
8.3%
|
|
| 1973 | 2 |
16.7%
|
|
| 1974 | 5 |
41.7%
|
|
| 1975 | 1 |
8.3%
|
|
| 1976 | 1 |
8.3%
|
|
| 1978 | 1 |
8.3%
|
|
| 1983 | 1 |
8.3%
|
|
| Sysmiss | 793 |