| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 274 |
8.8%
|
| 1972 | 1 |
0%
|
|
| 1974 | 2 |
0.1%
|
|
| 1975 | 2 |
0.1%
|
|
| 1978 | 1 |
0%
|
|
| 1979 | 1 |
0%
|
|
| 1982 | 1 |
0%
|
|
| 1984 | 1 |
0%
|
|
| 1985 | 2 |
0.1%
|
|
| 1986 | 1 |
0%
|
|
| 1987 | 2 |
0.1%
|
|
| 1990 | 5 |
0.2%
|
|
| 1991 | 3 |
0.1%
|
|
| 1992 | 3 |
0.1%
|
|
| 1993 | 4 |
0.1%
|
|
| 1994 | 1 |
0%
|
|
| 1996 | 3 |
0.1%
|
|
| 1997 | 2 |
0.1%
|
|
| 1998 | 1 |
0%
|
|
| 1999 | 3 |
0.1%
|
|
| 2000 | 16 |
0.5%
|
|
| 2001 | 5 |
0.2%
|
|
| 2002 | 4 |
0.1%
|
|
| 2003 | 7 |
0.2%
|
|
| 2004 | 3 |
0.1%
|
|
| 2005 | 4 |
0.1%
|
|
| 2006 | 3 |
0.1%
|
|
| 2007 | 3 |
0.1%
|
|
| 2008 | 13 |
0.4%
|
|
| 2009 | 9 |
0.3%
|
|
| 2010 | 48 |
1.5%
|
|
| 2011 | 7 |
0.2%
|
|
| 2012 | 19 |
0.6%
|
|
| 2013 | 25 |
0.8%
|
|
| 2014 | 25 |
0.8%
|
|
| 2015 | 84 |
2.7%
|
|
| 2016 | 47 |
1.5%
|
|
| 2017 | 60 |
1.9%
|
|
| 2018 | 148 |
4.8%
|
|
| 2019 | 221 |
7.1%
|
|
| 2020 | 393 |
12.7%
|
|
| 2021 | 356 |
11.5%
|
|
| 2022 | 517 |
16.7%
|
|
| 2023 | 775 |
25%
|