| Value | Category | Cases | |
|---|---|---|---|
| 1998 | 1 |
2.1%
|
|
| 2004 | 3 |
6.4%
|
|
| 2005 | 1 |
2.1%
|
|
| 2006 | 2 |
4.3%
|
|
| 2008 | 3 |
6.4%
|
|
| 2009 | 2 |
4.3%
|
|
| 2010 | 4 |
8.5%
|
|
| 2011 | 4 |
8.5%
|
|
| 2012 | 7 |
14.9%
|
|
| 2013 | 4 |
8.5%
|
|
| 2014 | 11 |
23.4%
|
|
| 2015 | 4 |
8.5%
|
|
| 9998 | don't know | 1 |
2.1%
|
| Sysmiss | 12868 |