| Value | Category | Cases | |
|---|---|---|---|
| 1975 | 1 |
0.1%
|
|
| 1988 | 1 |
0.1%
|
|
| 1998 | 2 |
0.1%
|
|
| 1999 | 3 |
0.2%
|
|
| 2000 | 7 |
0.4%
|
|
| 2001 | 6 |
0.3%
|
|
| 2002 | 7 |
0.4%
|
|
| 2003 | 5 |
0.3%
|
|
| 2004 | 5 |
0.3%
|
|
| 2005 | 21 |
1.1%
|
|
| 2006 | 12 |
0.6%
|
|
| 2007 | 15 |
0.8%
|
|
| 2008 | 17 |
0.9%
|
|
| 2009 | 30 |
1.6%
|
|
| 2010 | 64 |
3.4%
|
|
| 2011 | 61 |
3.3%
|
|
| 2012 | 133 |
7.1%
|
|
| 2013 | 265 |
14.2%
|
|
| 2014 | 579 |
31.1%
|
|
| 2015 | 578 |
31.1%
|
|
| 2016 | 34 |
1.8%
|
|
| 9998 | don't know/don't remember | 15 |
0.8%
|
| Sysmiss | 33922 |