| Value | Category | Cases | |
|---|---|---|---|
| 2012 | 3 | 
                                                                 
                                    
                                    37.5%
                                 
                                                             | 
                                                        
                    |
| 2013 | 4 | 
                                                                 
                                    
                                    50%
                                 
                                                             | 
                                                        
                    |
| 9998 | don't know | 1 | 
                                                                 
                                    
                                    12.5%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 16422 |