| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 13 |
4.4%
|
| 2014 | 3 |
1%
|
|
| 2015 | 7 |
2.4%
|
|
| 2016 | 24 |
8.1%
|
|
| 2017 | 53 |
18%
|
|
| 2018 | 167 |
56.6%
|
|
| 2019 | 28 |
9.5%
|
|
| Sysmiss | 944 |