| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 31 | 
                                                                 
                                    
                                    9.3%
                                 
                                                             | 
                                                        
                    |
| 1997 | 119 | 
                                                                 
                                    
                                    35.7%
                                 
                                                             | 
                                                        
                    |
| 1998 | 95 | 
                                                                 
                                    
                                    28.5%
                                 
                                                             | 
                                                        
                    |
| 1999 | 62 | 
                                                                 
                                    
                                    18.6%
                                 
                                                             | 
                                                        
                    |
| 2000 | 25 | 
                                                                 
                                    
                                    7.5%
                                 
                                                             | 
                                                        
                    |
| 9997 | inconsistent | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    
| 9998 | dk | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 6422 |