| Value | Category | Cases | |
|---|---|---|---|
| 1970 | 2 |
8.7%
|
|
| 1971 | 1 |
4.3%
|
|
| 1974 | 2 |
8.7%
|
|
| 1975 | 2 |
8.7%
|
|
| 1976 | 1 |
4.3%
|
|
| 1977 | 4 |
17.4%
|
|
| 1978 | 4 |
17.4%
|
|
| 1979 | 3 |
13%
|
|
| 1980 | 2 |
8.7%
|
|
| 1982 | 1 |
4.3%
|
|
| 1983 | 1 |
4.3%
|
|
| Sysmiss | 782 |