| Value | Category | Cases | |
|---|---|---|---|
| 1976 | 1 |
9.1%
|
|
| 1989 | 1 |
9.1%
|
|
| 1990 | 1 |
9.1%
|
|
| 1991 | 3 |
27.3%
|
|
| 1993 | 2 |
18.2%
|
|
| 1994 | 1 |
9.1%
|
|
| 1998 | 1 |
9.1%
|
|
| 1999 | 1 |
9.1%
|
|
| 9998 | don't know | 0 |
0%
|
| Sysmiss | 16419 |