| Value | Category | Cases | |
|---|---|---|---|
| -99 | Do not know | 0 |
0%
|
| 2015 | 1 |
20%
|
|
| 2016 | 1 |
20%
|
|
| 2017 | 2 |
40%
|
|
| 2018 | 1 |
20%
|
|
| Sysmiss | 123 |