| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.8%
|
| 1987 | 1 |
0.8%
|
|
| 1995 | 1 |
0.8%
|
|
| 1997 | 1 |
0.8%
|
|
| 1998 | 1 |
0.8%
|
|
| 1999 | 1 |
0.8%
|
|
| 2000 | 4 |
3.3%
|
|
| 2001 | 1 |
0.8%
|
|
| 2002 | 1 |
0.8%
|
|
| 2003 | 5 |
4.2%
|
|
| 2004 | 2 |
1.7%
|
|
| 2006 | 4 |
3.3%
|
|
| 2007 | 2 |
1.7%
|
|
| 2008 | 4 |
3.3%
|
|
| 2009 | 6 |
5%
|
|
| 2010 | 5 |
4.2%
|
|
| 2011 | 5 |
4.2%
|
|
| 2012 | 4 |
3.3%
|
|
| 2013 | 3 |
2.5%
|
|
| 2014 | 12 |
10%
|
|
| 2015 | 13 |
10.8%
|
|
| 2016 | 13 |
10.8%
|
|
| 2017 | 18 |
15%
|
|
| 2018 | 11 |
9.2%
|
|
| 2019 | 1 |
0.8%
|