| Value | Category | Cases | |
|---|---|---|---|
| 99 | Missing | 1 |
2.2%
|
| 1988 | 29 |
63%
|
|
| 1989 | 3 |
6.5%
|
|
| 1990 | 1 |
2.2%
|
|
| 1991 | 2 |
4.3%
|
|
| 1993 | 1 |
2.2%
|
|
| 1994 | 4 |
8.7%
|
|
| 1995 | 3 |
6.5%
|
|
| 1998 | 1 |
2.2%
|
|
| 2000 | 1 |
2.2%
|
|
| Sysmiss | 1679 |