| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 14 |
40%
|
| 1999 | 1 |
2.9%
|
|
| 2000 | 1 |
2.9%
|
|
| 2002 | 1 |
2.9%
|
|
| 2003 | 5 |
14.3%
|
|
| 2004 | 5 |
14.3%
|
|
| 2005 | 6 |
17.1%
|
|
| 2006 | 1 |
2.9%
|
|
| 2007 | 1 |
2.9%
|
|
| Sysmiss | 151 |