| Value | Category | Cases | |
|---|---|---|---|
| -998 | Don't Know | 0 |
0%
|
| 2000 | 3 |
50%
|
|
| 2008 | 1 |
16.7%
|
|
| 2010 | 1 |
16.7%
|
|
| 2015 | 1 |
16.7%
|
|
| Sysmiss | 113 |