| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| 2009 | 1 |
3.6%
|
|
| 2014 | 1 |
3.6%
|
|
| 2015 | 6 |
21.4%
|
|
| 2016 | 7 |
25%
|
|
| 2017 | 10 |
35.7%
|
|
| 2018 | 1 |
3.6%
|
|
| 2019 | 2 |
7.1%
|
|
| Sysmiss | 222 |