| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 18 |
40.9%
|
| 1930 | 1 |
2.3%
|
|
| 1980 | 1 |
2.3%
|
|
| 1985 | 1 |
2.3%
|
|
| 1989 | 1 |
2.3%
|
|
| 1990 | 3 |
6.8%
|
|
| 1991 | 1 |
2.3%
|
|
| 1993 | 1 |
2.3%
|
|
| 1998 | 1 |
2.3%
|
|
| 2000 | 1 |
2.3%
|
|
| 2004 | 1 |
2.3%
|
|
| 2005 | 1 |
2.3%
|
|
| 2006 | 1 |
2.3%
|
|
| 2007 | 1 |
2.3%
|
|
| 2008 | 1 |
2.3%
|
|
| 2009 | 1 |
2.3%
|
|
| 2010 | 3 |
6.8%
|
|
| 2013 | 2 |
4.5%
|
|
| 2014 | 1 |
2.3%
|
|
| 2015 | 1 |
2.3%
|
|
| 2017 | 1 |
2.3%
|
|
| 2021 | 1 |
2.3%
|
|
| Sysmiss | 109 |