| Value | Category | Cases | |
|---|---|---|---|
| 1981 | 1 |
0.1%
|
|
| 1984 | 2 |
0.2%
|
|
| 1985 | 4 |
0.3%
|
|
| 1987 | 3 |
0.3%
|
|
| 1990 | 3 |
0.3%
|
|
| 1991 | 2 |
0.2%
|
|
| 1992 | 1 |
0.1%
|
|
| 1993 | 24 |
2%
|
|
| 1994 | 392 |
32.9%
|
|
| 1995 | 399 |
33.5%
|
|
| 1996 | 277 |
23.3%
|
|
| 1997 | 82 |
6.9%
|
|
| Sysmiss | 45 |