| Value | Category | Cases | |
|---|---|---|---|
| 0 | not given | 118 | 
                                    
                                    24.6%
                                 | 
| 1995 | 29 | 
                                    
                                    6.1%
                                 | |
| 1996 | 89 | 
                                    
                                    18.6%
                                 | |
| 1997 | 95 | 
                                    
                                    19.8%
                                 | |
| 1998 | 65 | 
                                    
                                    13.6%
                                 | |
| 1999 | 27 | 
                                    
                                    5.6%
                                 | |
| 2000 | 14 | 
                                    
                                    2.9%
                                 | |
| 4444 | marked on card | 36 | 
                                    
                                    7.5%
                                 | 
| 6666 | mother reported | 6 | 
                                    
                                    1.3%
                                 | 
| 9997 | inconsistent | 0 | 
                                    
                                    0%
                                 | 
| 9998 | dk | 0 | 
                                    
                                    0%
                                 | 
| 9999 | missing | 0 | 
                                    
                                    0%
                                 | 
| Sysmiss | 14872 |