| Value | Category | Cases | |
|---|---|---|---|
| 1995 | 7 |
1%
|
|
| 1996 | 41 |
6%
|
|
| 1997 | 61 |
8.9%
|
|
| 1998 | 122 |
17.8%
|
|
| 1999 | 149 |
21.8%
|
|
| 2000 | 103 |
15%
|
|
| 9997 | Missing | 202 |
29.5%
|
| Sysmiss | 2019 |