| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
4%
|
| 1992 | 2 |
4%
|
|
| 1994 | 1 |
2%
|
|
| 1995 | 1 |
2%
|
|
| 1996 | 2 |
4%
|
|
| 1997 | 1 |
2%
|
|
| 1998 | 1 |
2%
|
|
| 2000 | 2 |
4%
|
|
| 2001 | 2 |
4%
|
|
| 2002 | 1 |
2%
|
|
| 2005 | 1 |
2%
|
|
| 2006 | 2 |
4%
|
|
| 2007 | 1 |
2%
|
|
| 2008 | 3 |
6%
|
|
| 2009 | 1 |
2%
|
|
| 2010 | 1 |
2%
|
|
| 2011 | 4 |
8%
|
|
| 2012 | 3 |
6%
|
|
| 2013 | 1 |
2%
|
|
| 2014 | 1 |
2%
|
|
| 2015 | 1 |
2%
|
|
| 2016 | 2 |
4%
|
|
| 2017 | 2 |
4%
|
|
| 2018 | 4 |
8%
|
|
| 2019 | 1 |
2%
|
|
| 2020 | 1 |
2%
|
|
| 2021 | 1 |
2%
|
|
| 2022 | 4 |
8%
|
|
| 2023 | 1 |
2%
|
|
| Sysmiss | 102 |