| Value | Category | Cases | |
|---|---|---|---|
| 1 | Yes, it is essential | 992 | 
                                    
                                    72.8%
                                 | 
| 2 | Yes, but not essential | 141 | 
                                    
                                    10.3%
                                 | 
| 3 | No, it is not useful | 95 | 
                                    
                                    7%
                                 | 
| 4 | Other | 135 | 
                                    
                                    9.9%
                                 | 
| Sysmiss | 118 |