| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 3 | 
                                    
                                    0.7%
                                 | |
| 1997 | 18 | 
                                    
                                    4.3%
                                 | |
| 1998 | 19 | 
                                    
                                    4.5%
                                 | |
| 1999 | 50 | 
                                    
                                    11.9%
                                 | |
| 2000 | 56 | 
                                    
                                    13.4%
                                 | |
| 2001 | 138 | 
                                    
                                    32.9%
                                 | |
| 2002 | 135 | 
                                    
                                    32.2%
                                 | |
| Sysmiss | 798 |