| Value | Category | Cases | |
|---|---|---|---|
| 2007 | 28 | 
                                    
                                    0.4%
                                 | |
| 2008 | 184 | 
                                    
                                    2.6%
                                 | |
| 2009 | 460 | 
                                    
                                    6.6%
                                 | |
| 2010 | 545 | 
                                    
                                    7.8%
                                 | |
| 2011 | 665 | 
                                    
                                    9.5%
                                 | |
| 2012 | 698 | 
                                    
                                    10%
                                 | |
| 2013 | 733 | 
                                    
                                    10.5%
                                 | |
| 2014 | 842 | 
                                    
                                    12.1%
                                 | |
| 2015 | 884 | 
                                    
                                    12.7%
                                 | |
| 2016 | 913 | 
                                    
                                    13.1%
                                 | |
| 2017 | 7 | 
                                    
                                    0.1%
                                 | |
| 3333 | Missing | 40 | 
                                    
                                    0.6%
                                 | 
| 5555 | Not applicable | 0 | 
                                    
                                    0%
                                 | 
| 8888 | Refused | 1 | 
                                    
                                    0%
                                 | 
| 9999 | Don't know | 985 | 
                                    
                                    14.1%
                                 | 
| Sysmiss | 8008 |