| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 8 |
5.3%
|
| 2000 | 2 |
1.3%
|
|
| 2010 | 1 |
0.7%
|
|
| 2012 | 4 |
2.7%
|
|
| 2013 | 2 |
1.3%
|
|
| 2014 | 5 |
3.3%
|
|
| 2015 | 12 |
8%
|
|
| 2016 | 19 |
12.7%
|
|
| 2017 | 27 |
18%
|
|
| 2018 | 56 |
37.3%
|
|
| 2019 | 14 |
9.3%
|
|
| Sysmiss | 227 |