| Value | Category | Cases | |
|---|---|---|---|
| 1980 | 1 |
1.3%
|
|
| 1994 | 5 |
6.3%
|
|
| 1995 | 45 |
57%
|
|
| 1996 | 9 |
11.4%
|
|
| 1997 | 19 |
24.1%
|
|
| Sysmiss | 234 |