| Value | Category | Cases | |
|---|---|---|---|
| 1993 | 1 | 
                                    
                                    0.2%
                                 | |
| 1997 | 13 | 
                                    
                                    3.1%
                                 | |
| 1998 | 48 | 
                                    
                                    11.6%
                                 | |
| 1999 | 106 | 
                                    
                                    25.5%
                                 | |
| 2000 | 98 | 
                                    
                                    23.6%
                                 | |
| 2001 | 124 | 
                                    
                                    29.9%
                                 | |
| 2002 | 25 | 
                                    
                                    6%
                                 | |
| Sysmiss | 7634 |