| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
1.3%
|
| 1990 | 1 |
0.7%
|
|
| 1992 | 1 |
0.7%
|
|
| 1995 | 1 |
0.7%
|
|
| 1998 | 2 |
1.3%
|
|
| 2002 | 1 |
0.7%
|
|
| 2006 | 2 |
1.3%
|
|
| 2007 | 2 |
1.3%
|
|
| 2009 | 1 |
0.7%
|
|
| 2010 | 2 |
1.3%
|
|
| 2011 | 1 |
0.7%
|
|
| 2013 | 2 |
1.3%
|
|
| 2015 | 1 |
0.7%
|
|
| 2016 | 4 |
2.6%
|
|
| 2017 | 3 |
2%
|
|
| NA | 125 |
82.8%
|