| Value | Category | Cases | |
|---|---|---|---|
| -3 | 52 | 
                                    
                                    6.5%
                                 | |
| 2000 | 3 | 
                                    
                                    0.4%
                                 | |
| 2001 | 6 | 
                                    
                                    0.8%
                                 | |
| 2002 | 6 | 
                                    
                                    0.8%
                                 | |
| 2003 | 11 | 
                                    
                                    1.4%
                                 | |
| 2004 | 25 | 
                                    
                                    3.1%
                                 | |
| 2005 | 35 | 
                                    
                                    4.4%
                                 | |
| 2006 | 42 | 
                                    
                                    5.3%
                                 | |
| 2007 | 50 | 
                                    
                                    6.3%
                                 | |
| 2008 | 42 | 
                                    
                                    5.3%
                                 | |
| 2009 | 46 | 
                                    
                                    5.8%
                                 | |
| 2010 | 71 | 
                                    
                                    8.9%
                                 | |
| 2011 | 82 | 
                                    
                                    10.3%
                                 | |
| 2012 | 88 | 
                                    
                                    11%
                                 | |
| 2013 | 81 | 
                                    
                                    10.1%
                                 | |
| 2014 | 87 | 
                                    
                                    10.9%
                                 | |
| 2015 | 20 | 
                                    
                                    2.5%
                                 | |
| 3333 | Missing | 1 | 
                                    
                                    0.1%
                                 | 
| 5555 | Not applicable | 0 | 
                                    
                                    0%
                                 | 
| 8888 | Refused | 0 | 
                                    
                                    0%
                                 | 
| 9999 | Don't know | 52 | 
                                    
                                    6.5%
                                 | 
| Sysmiss | 13171 |