| Value | Category | Cases | |
|---|---|---|---|
| 1995 | 12 | 
                                                                 
                                    
                                    0.7%
                                 
                                                             | 
                                                        
                    |
| 1996 | 127 | 
                                                                 
                                    
                                    7.4%
                                 
                                                             | 
                                                        
                    |
| 1997 | 164 | 
                                                                 
                                    
                                    9.6%
                                 
                                                             | 
                                                        
                    |
| 1998 | 297 | 
                                                                 
                                    
                                    17.3%
                                 
                                                             | 
                                                        
                    |
| 1999 | 541 | 
                                                                 
                                    
                                    31.5%
                                 
                                                             | 
                                                        
                    |
| 2000 | 576 | 
                                                                 
                                    
                                    33.5%
                                 
                                                             | 
                                                        
                    |
| 9997 | inconsistent | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| 9998 | dk | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 5038 |