| Value | Category | Cases | |
|---|---|---|---|
| 1978 | 1 |
4%
|
|
| 1979 | 1 |
4%
|
|
| 1981 | 2 |
8%
|
|
| 1982 | 1 |
4%
|
|
| 1983 | 2 |
8%
|
|
| 1984 | 4 |
16%
|
|
| 1985 | 1 |
4%
|
|
| 1986 | 3 |
12%
|
|
| 1987 | 3 |
12%
|
|
| 1988 | 3 |
12%
|
|
| 1990 | 2 |
8%
|
|
| 1992 | 2 |
8%
|
|
| Sysmiss | 1406 |