| Value | Category | Cases | |
|---|---|---|---|
| 1972 | 1 | 
                                                                 
                                    
                                    0.5%
                                 
                                                             | 
                                                        
                    |
| 1990 | 1 | 
                                                                 
                                    
                                    0.5%
                                 
                                                             | 
                                                        
                    |
| 1992 | 1 | 
                                                                 
                                    
                                    0.5%
                                 
                                                             | 
                                                        
                    |
| 1994 | 3 | 
                                                                 
                                    
                                    1.6%
                                 
                                                             | 
                                                        
                    |
| 1995 | 5 | 
                                                                 
                                    
                                    2.6%
                                 
                                                             | 
                                                        
                    |
| 1996 | 80 | 
                                                                 
                                    
                                    41.5%
                                 
                                                             | 
                                                        
                    |
| 1997 | 57 | 
                                                                 
                                    
                                    29.5%
                                 
                                                             | 
                                                        
                    |
| 1998 | 44 | 
                                                                 
                                    
                                    22.8%
                                 
                                                             | 
                                                        
                    |
| 7777 | Don't Know | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| 9999 | Refused | 1 | 
                                                                 
                                    
                                    0.5%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 5078 |