| Value | Category | Cases | |
|---|---|---|---|
| 1973 | 1 |
7.7%
|
|
| 1974 | 1 |
7.7%
|
|
| 1976 | 1 |
7.7%
|
|
| 1977 | 2 |
15.4%
|
|
| 1978 | 2 |
15.4%
|
|
| 1979 | 1 |
7.7%
|
|
| 1980 | 2 |
15.4%
|
|
| 1981 | 1 |
7.7%
|
|
| 1984 | 1 |
7.7%
|
|
| 1988 | 1 |
7.7%
|
|
| Sysmiss | 8431 |