| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 18 |
13.4%
|
| 2002 | 1 |
0.7%
|
|
| 2004 | 1 |
0.7%
|
|
| 2006 | 1 |
0.7%
|
|
| 2009 | 1 |
0.7%
|
|
| 2010 | 6 |
4.5%
|
|
| 2011 | 1 |
0.7%
|
|
| 2012 | 4 |
3%
|
|
| 2014 | 2 |
1.5%
|
|
| 2015 | 5 |
3.7%
|
|
| 2016 | 4 |
3%
|
|
| 2017 | 7 |
5.2%
|
|
| 2018 | 10 |
7.5%
|
|
| 2019 | 14 |
10.4%
|
|
| 2020 | 28 |
20.9%
|
|
| 2021 | 13 |
9.7%
|
|
| 2022 | 16 |
11.9%
|
|
| 2023 | 2 |
1.5%
|
|
| Sysmiss | 464 |