| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
0.5%
|
| -7 | Never regiestered (spontaneous) | 0 |
0%
|
| 1959 | 1 |
0.3%
|
|
| 1962 | 1 |
0.3%
|
|
| 1974 | 1 |
0.3%
|
|
| 1981 | 1 |
0.3%
|
|
| 1987 | 1 |
0.3%
|
|
| 1989 | 2 |
0.5%
|
|
| 1990 | 2 |
0.5%
|
|
| 1991 | 2 |
0.5%
|
|
| 1993 | 2 |
0.5%
|
|
| 1994 | 1 |
0.3%
|
|
| 1995 | 2 |
0.5%
|
|
| 1996 | 1 |
0.3%
|
|
| 1997 | 3 |
0.8%
|
|
| 1998 | 2 |
0.5%
|
|
| 1999 | 3 |
0.8%
|
|
| 2000 | 10 |
2.6%
|
|
| 2001 | 3 |
0.8%
|
|
| 2002 | 5 |
1.3%
|
|
| 2003 | 6 |
1.5%
|
|
| 2004 | 10 |
2.6%
|
|
| 2005 | 13 |
3.3%
|
|
| 2006 | 8 |
2%
|
|
| 2007 | 8 |
2%
|
|
| 2008 | 9 |
2.3%
|
|
| 2009 | 11 |
2.8%
|
|
| 2010 | 11 |
2.8%
|
|
| 2011 | 10 |
2.6%
|
|
| 2012 | 11 |
2.8%
|
|
| 2013 | 19 |
4.8%
|
|
| 2014 | 24 |
6.1%
|
|
| 2015 | 27 |
6.9%
|
|
| 2016 | 30 |
7.7%
|
|
| 2017 | 18 |
4.6%
|
|
| 2018 | 33 |
8.4%
|
|
| 2019 | 19 |
4.8%
|
|
| 2020 | 34 |
8.7%
|
|
| 2021 | 19 |
4.8%
|
|
| 2022 | 23 |
5.9%
|
|
| 2023 | 4 |
1%
|