| Value | Category | Cases | |
|---|---|---|---|
| 1 | months | 9 | 
                                    
                                    1.4%
                                 | 
| 2 | years | 505 | 
                                    
                                    80.3%
                                 | 
| 9 | special answers | 115 | 
                                    
                                    18.3%
                                 | 
| Sysmiss | 14722 |