| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| 1901 | 1 |
1%
|
|
| 1940 | 2 |
1.9%
|
|
| 1962 | 1 |
1%
|
|
| 1963 | 1 |
1%
|
|
| 1972 | 2 |
1.9%
|
|
| 1974 | 1 |
1%
|
|
| 1979 | 1 |
1%
|
|
| 1985 | 1 |
1%
|
|
| 1986 | 1 |
1%
|
|
| 1987 | 1 |
1%
|
|
| 1990 | 4 |
3.9%
|
|
| 1992 | 1 |
1%
|
|
| 1993 | 4 |
3.9%
|
|
| 1994 | 2 |
1.9%
|
|
| 1995 | 4 |
3.9%
|
|
| 1997 | 1 |
1%
|
|
| 1998 | 3 |
2.9%
|
|
| 1999 | 4 |
3.9%
|
|
| 2000 | 6 |
5.8%
|
|
| 2001 | 2 |
1.9%
|
|
| 2003 | 3 |
2.9%
|
|
| 2004 | 1 |
1%
|
|
| 2005 | 2 |
1.9%
|
|
| 2006 | 3 |
2.9%
|
|
| 2008 | 5 |
4.9%
|
|
| 2009 | 3 |
2.9%
|
|
| 2010 | 1 |
1%
|
|
| 2011 | 2 |
1.9%
|
|
| 2012 | 7 |
6.8%
|
|
| 2013 | 2 |
1.9%
|
|
| 2014 | 3 |
2.9%
|
|
| 2015 | 5 |
4.9%
|
|
| 2016 | 3 |
2.9%
|
|
| 2017 | 6 |
5.8%
|
|
| 2018 | 3 |
2.9%
|
|
| 2019 | 3 |
2.9%
|
|
| 2020 | 3 |
2.9%
|
|
| 2021 | 4 |
3.9%
|
|
| 2022 | 1 |
1%
|