| Value | Category | Cases | |
|---|---|---|---|
| 2002 | 2 | 
                                                                 
                                    
                                    3.9%
                                 
                                                             | 
                                                        
                    |
| 2003 | 6 | 
                                                                 
                                    
                                    11.8%
                                 
                                                             | 
                                                        
                    |
| 2004 | 13 | 
                                                                 
                                    
                                    25.5%
                                 
                                                             | 
                                                        
                    |
| 2005 | 29 | 
                                                                 
                                    
                                    56.9%
                                 
                                                             | 
                                                        
                    |
| 9999 | 9999. Don't know | 1 | 
                                                                 
                                    
                                    2%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 948 |