| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 9 | 
                                                                 
                                    
                                    9.7%
                                 
                                                             | 
                                                        
                    |
| 1997 | 12 | 
                                                                 
                                    
                                    12.9%
                                 
                                                             | 
                                                        
                    |
| 1998 | 17 | 
                                                                 
                                    
                                    18.3%
                                 
                                                             | 
                                                        
                    |
| 1999 | 22 | 
                                                                 
                                    
                                    23.7%
                                 
                                                             | 
                                                        
                    |
| 2000 | 33 | 
                                                                 
                                    
                                    35.5%
                                 
                                                             | 
                                                        
                    |
| 9997 | inconsistent | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| 9998 | dk | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 6299 |