| Value | Category | Cases | |
|---|---|---|---|
| 1975 | 3 |
9.4%
|
|
| 1977 | 1 |
3.1%
|
|
| 1978 | 4 |
12.5%
|
|
| 1979 | 4 |
12.5%
|
|
| 1980 | 3 |
9.4%
|
|
| 1981 | 2 |
6.3%
|
|
| 1982 | 3 |
9.4%
|
|
| 1983 | 3 |
9.4%
|
|
| 1984 | 3 |
9.4%
|
|
| 1985 | 3 |
9.4%
|
|
| 1986 | 1 |
3.1%
|
|
| 1987 | 1 |
3.1%
|
|
| 1990 | 1 |
3.1%
|
|
| Sysmiss | 8412 |