| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
2.8%
|
| 1989 | 2 |
5.6%
|
|
| 1990 | 1 |
2.8%
|
|
| 1992 | 1 |
2.8%
|
|
| 1998 | 2 |
5.6%
|
|
| 2002 | 4 |
11.1%
|
|
| 2003 | 2 |
5.6%
|
|
| 2004 | 1 |
2.8%
|
|
| 2005 | 1 |
2.8%
|
|
| 2006 | 3 |
8.3%
|
|
| 2007 | 1 |
2.8%
|
|
| 2009 | 2 |
5.6%
|
|
| 2010 | 2 |
5.6%
|
|
| 2011 | 1 |
2.8%
|
|
| 2012 | 1 |
2.8%
|
|
| 2014 | 5 |
13.9%
|
|
| 2016 | 3 |
8.3%
|
|
| 2017 | 1 |
2.8%
|
|
| 2019 | 1 |
2.8%
|
|
| 2020 | 1 |
2.8%
|
|
| Sysmiss | 114 |