| Value | Category | Cases | |
|---|---|---|---|
| 1991 | 1 |
0.4%
|
|
| 1992 | 11 |
4.1%
|
|
| 1993 | 26 |
9.6%
|
|
| 1994 | 36 |
13.3%
|
|
| 1995 | 47 |
17.4%
|
|
| 1996 | 80 |
29.6%
|
|
| 1997 | 68 |
25.2%
|
|
| 1998 | 1 |
0.4%
|
|
| Sysmiss | 10086 |