| Value | Category | Cases | |
|---|---|---|---|
| 1979 | 1 |
3.2%
|
|
| 1982 | 6 |
19.4%
|
|
| 1983 | 6 |
19.4%
|
|
| 1984 | 5 |
16.1%
|
|
| 1985 | 6 |
19.4%
|
|
| 1986 | 3 |
9.7%
|
|
| 1988 | 3 |
9.7%
|
|
| 1989 | 1 |
3.2%
|