| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 174 | 
                                    
                                    9.6%
                                 | |
| 1997 | 289 | 
                                    
                                    15.9%
                                 | |
| 1998 | 334 | 
                                    
                                    18.4%
                                 | |
| 1999 | 477 | 
                                    
                                    26.2%
                                 | |
| 2000 | 546 | 
                                    
                                    30%
                                 | |
| 9997 | inconsistent | 0 | 
                                    
                                    0%
                                 | 
| 9998 | dk | 0 | 
                                    
                                    0%
                                 | 
| Sysmiss | 13126 |