| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 20 |
31.7%
|
| 1999 | 1 |
1.6%
|
|
| 2002 | 1 |
1.6%
|
|
| 2004 | 1 |
1.6%
|
|
| 2006 | 2 |
3.2%
|
|
| 2008 | 1 |
1.6%
|
|
| 2009 | 1 |
1.6%
|
|
| 2010 | 3 |
4.8%
|
|
| 2011 | 1 |
1.6%
|
|
| 2012 | 1 |
1.6%
|
|
| 2013 | 2 |
3.2%
|
|
| 2014 | 2 |
3.2%
|
|
| 2015 | 2 |
3.2%
|
|
| 2016 | 1 |
1.6%
|
|
| 2017 | 3 |
4.8%
|
|
| 2018 | 2 |
3.2%
|
|
| 2019 | 3 |
4.8%
|
|
| 2020 | 1 |
1.6%
|
|
| 2021 | 3 |
4.8%
|
|
| 2022 | 7 |
11.1%
|
|
| 2023 | 5 |
7.9%
|
|
| Sysmiss | 305 |