| Value | Category | Cases | |
|---|---|---|---|
| 1973 | 1 |
3.7%
|
|
| 1976 | 1 |
3.7%
|
|
| 1982 | 1 |
3.7%
|
|
| 1986 | 2 |
7.4%
|
|
| 1988 | 1 |
3.7%
|
|
| 1989 | 1 |
3.7%
|
|
| 1990 | 1 |
3.7%
|
|
| 1991 | 5 |
18.5%
|
|
| 1993 | 4 |
14.8%
|
|
| 1994 | 1 |
3.7%
|
|
| 1998 | 1 |
3.7%
|
|
| 1999 | 1 |
3.7%
|
|
| 2002 | 1 |
3.7%
|
|
| 9998 | don't know | 6 |
22.2%
|
| Sysmiss | 16403 |