| Value | Category | Cases | |
|---|---|---|---|
| 1986 | 1 |
0.8%
|
|
| 1987 | 1 |
0.8%
|
|
| 1989 | 2 |
1.7%
|
|
| 1990 | 7 |
5.9%
|
|
| 1991 | 3 |
2.5%
|
|
| 1992 | 16 |
13.4%
|
|
| 1993 | 9 |
7.6%
|
|
| 1994 | 34 |
28.6%
|
|
| 1995 | 13 |
10.9%
|
|
| 1996 | 15 |
12.6%
|
|
| 1997 | 18 |
15.1%
|
|
| Sysmiss | 803 |