| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 12 |
16.2%
|
| 2004 | 1 |
1.4%
|
|
| 2005 | 1 |
1.4%
|
|
| 2006 | 1 |
1.4%
|
|
| 2007 | 2 |
2.7%
|
|
| 2008 | 2 |
2.7%
|
|
| 9888 | Continuing | 55 |
74.3%
|
| Sysmiss | 112 |