| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 100 | 
                                                                 
                                    
                                    28.7%
                                 
                                                             | 
                                                        
                    |
| 1997 | 117 | 
                                                                 
                                    
                                    33.5%
                                 
                                                             | 
                                                        
                    |
| 1998 | 92 | 
                                                                 
                                    
                                    26.4%
                                 
                                                             | 
                                                        
                    |
| 1999 | 26 | 
                                                                 
                                    
                                    7.4%
                                 
                                                             | 
                                                        
                    |
| 2000 | 13 | 
                                                                 
                                    
                                    3.7%
                                 
                                                             | 
                                                        
                    |
| 9997 | inconsistent | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    
| 9998 | dk | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 6406 |