| Value | Category | Cases | |
|---|---|---|---|
| 1994 | 4 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 1995 | 22 | 
                                                                 
                                    
                                    1.7%
                                 
                                                             | 
                                                        
                    |
| 1996 | 144 | 
                                                                 
                                    
                                    11.1%
                                 
                                                             | 
                                                        
                    |
| 1997 | 266 | 
                                                                 
                                    
                                    20.5%
                                 
                                                             | 
                                                        
                    |
| 1998 | 323 | 
                                                                 
                                    
                                    24.8%
                                 
                                                             | 
                                                        
                    |
| 1999 | 404 | 
                                                                 
                                    
                                    31.1%
                                 
                                                             | 
                                                        
                    |
| 2000 | 137 | 
                                                                 
                                    
                                    10.5%
                                 
                                                             | 
                                                        
                    |
| 9997 | inconsistent | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| 9998 | dk | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 10936 |