| Value | Category | Cases | |
|---|---|---|---|
| 1995 | 1 |
6.7%
|
|
| 1998 | 2 |
13.3%
|
|
| 1999 | 2 |
13.3%
|
|
| 2000 | 3 |
20%
|
|
| 2002 | 2 |
13.3%
|
|
| 2003 | 3 |
20%
|
|
| 2004 | 2 |
13.3%
|
|
| 9997 | inconsistent | 0 |
0%
|
| 9998 | don't know | 0 |
0%
|
| Sysmiss | 197 |