| Value | Category | Cases | |
|---|---|---|---|
| 2001 | 15 |
7.9%
|
|
| 2002 | 39 |
20.5%
|
|
| 2003 | 54 |
28.4%
|
|
| 2004 | 34 |
17.9%
|
|
| 2005 | 38 |
20%
|
|
| 2006 | 10 |
5.3%
|
|
| 9997 | Inconsistent | 0 |
0%
|
| 9998 | DK | 0 |
0%
|
| 9999 | Missing | 0 |
0%
|
| Sysmiss | 2 |