| Value | Category | Cases | |
|---|---|---|---|
| 0 | not given | 115 | 
                                    
                                    24%
                                 | 
| 1995 | 28 | 
                                    
                                    5.8%
                                 | |
| 1996 | 91 | 
                                    
                                    19%
                                 | |
| 1997 | 93 | 
                                    
                                    19.4%
                                 | |
| 1998 | 63 | 
                                    
                                    13.2%
                                 | |
| 1999 | 28 | 
                                    
                                    5.8%
                                 | |
| 2000 | 15 | 
                                    
                                    3.1%
                                 | |
| 4444 | marked on card | 38 | 
                                    
                                    7.9%
                                 | 
| 6666 | mother reported | 8 | 
                                    
                                    1.7%
                                 | 
| 9997 | inconsistent | 0 | 
                                    
                                    0%
                                 | 
| 9998 | dk | 0 | 
                                    
                                    0%
                                 | 
| 9999 | missing | 0 | 
                                    
                                    0%
                                 | 
| Sysmiss | 14872 |