| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 63 |
36.2%
|
| 2004 | 1 |
0.6%
|
|
| 2005 | 2 |
1.1%
|
|
| 2006 | 1 |
0.6%
|
|
| 2008 | 6 |
3.4%
|
|
| 2009 | 1 |
0.6%
|
|
| 9888 | Continuing | 100 |
57.5%
|
| Sysmiss | 12 |