| Value | Category | Cases | |
|---|---|---|---|
| 2001 | 1 |
4.3%
|
|
| 2002 | 1 |
4.3%
|
|
| 2003 | 7 |
30.4%
|
|
| 2004 | 7 |
30.4%
|
|
| 2005 | 4 |
17.4%
|
|
| 2006 | 2 |
8.7%
|
|
| 9999 | 9999. Don't know | 1 |
4.3%
|
| Sysmiss | 76 |