| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 |
5%
|
| 1982 | 1 |
0.5%
|
|
| 1990 | 1 |
0.5%
|
|
| 1992 | 1 |
0.5%
|
|
| 1993 | 1 |
0.5%
|
|
| 1996 | 4 |
1.8%
|
|
| 1999 | 1 |
0.5%
|
|
| 2000 | 4 |
1.8%
|
|
| 2001 | 2 |
0.9%
|
|
| 2002 | 2 |
0.9%
|
|
| 2003 | 4 |
1.8%
|
|
| 2004 | 2 |
0.9%
|
|
| 2005 | 3 |
1.4%
|
|
| 2006 | 2 |
0.9%
|
|
| 2007 | 1 |
0.5%
|
|
| 2008 | 4 |
1.8%
|
|
| 2009 | 7 |
3.2%
|
|
| 2010 | 9 |
4.1%
|
|
| 2011 | 12 |
5.5%
|
|
| 2012 | 8 |
3.7%
|
|
| 2013 | 10 |
4.6%
|
|
| 2014 | 7 |
3.2%
|
|
| 2015 | 21 |
9.6%
|
|
| 2016 | 15 |
6.8%
|
|
| 2017 | 15 |
6.8%
|
|
| 2018 | 22 |
10%
|
|
| 2019 | 22 |
10%
|
|
| 2020 | 12 |
5.5%
|
|
| 2021 | 9 |
4.1%
|
|
| 2022 | 6 |
2.7%
|