| Value | Category | Cases | |
|---|---|---|---|
| -99 | Do not know | 1 |
20%
|
| 2002 | 1 |
20%
|
|
| 2008 | 1 |
20%
|
|
| 2015 | 1 |
20%
|
|
| 2017 | 1 |
20%
|
|
| Sysmiss | 123 |