| Value | Category | Cases | |
|---|---|---|---|
| 1975 | 1 |
16.7%
|
|
| 1978 | 1 |
16.7%
|
|
| 1979 | 1 |
16.7%
|
|
| 1980 | 1 |
16.7%
|
|
| 1982 | 1 |
16.7%
|
|
| 1983 | 1 |
16.7%
|
|
| Sysmiss | 1425 |