| Value | Category | Cases | |
|---|---|---|---|
| 1982 | 2 |
0.1%
|
|
| 1987 | 13 |
0.3%
|
|
| 1988 | 5 |
0.1%
|
|
| 1989 | 13 |
0.3%
|
|
| 1990 | 31 |
0.8%
|
|
| 1991 | 11 |
0.3%
|
|
| 1992 | 63 |
1.7%
|
|
| 1993 | 104 |
2.8%
|
|
| 1994 | 119 |
3.1%
|
|
| 1995 | 129 |
3.4%
|
|
| 1996 | 121 |
3.2%
|
|
| 1997 | 251 |
6.6%
|
|
| 1998 | 313 |
8.3%
|
|
| 1999 | 1253 |
33.2%
|
|
| 2000 | 776 |
20.5%
|
|
| 9998 | don't know | 574 |
15.2%
|
| Sysmiss | 11168 |