| Value | Category | Cases | |
|---|---|---|---|
| 2001 | 1 |
3.3%
|
|
| 2003 | 1 |
3.3%
|
|
| 2004 | 5 |
16.7%
|
|
| 2005 | 10 |
33.3%
|
|
| 2006 | 13 |
43.3%
|
|
| 9999 | 9999. Don't know | 0 |
0%
|
| Sysmiss | 969 |