| Value | Category | Cases | |
|---|---|---|---|
| 1 | NO DIFFICULTY | 5055 | 
                                    
                                    92.3%
                                 | 
| 2 | SOME DIFFICULTY | 216 | 
                                    
                                    3.9%
                                 | 
| 3 | A LOT OF DIFFICULTY | 27 | 
                                    
                                    0.5%
                                 | 
| 4 | CANNOT SEE AT ALL | 6 | 
                                    
                                    0.1%
                                 | 
| 9 | NO RESPONSE | 2 | 
                                    
                                    0%
                                 | 
| Sysmiss | 173 | 
                                    
                                    3.2%
                                 |