| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 9 |
10.2%
|
| 1957 | 1 |
1.1%
|
|
| 1975 | 2 |
2.3%
|
|
| 1980 | 1 |
1.1%
|
|
| 1985 | 1 |
1.1%
|
|
| 1992 | 1 |
1.1%
|
|
| 1997 | 1 |
1.1%
|
|
| 2002 | 1 |
1.1%
|
|
| 2005 | 1 |
1.1%
|
|
| 2006 | 2 |
2.3%
|
|
| 2008 | 2 |
2.3%
|
|
| 2009 | 3 |
3.4%
|
|
| 2010 | 1 |
1.1%
|
|
| 2012 | 2 |
2.3%
|
|
| 2013 | 1 |
1.1%
|
|
| 2014 | 7 |
8%
|
|
| 2015 | 4 |
4.5%
|
|
| 2016 | 4 |
4.5%
|
|
| 2017 | 7 |
8%
|
|
| 2018 | 3 |
3.4%
|
|
| 2019 | 9 |
10.2%
|
|
| 2020 | 6 |
6.8%
|
|
| 2021 | 4 |
4.5%
|
|
| 2022 | 9 |
10.2%
|
|
| 2023 | 6 |
6.8%
|
|
| Sysmiss | 937 |