| Value | Category | Cases | |
|---|---|---|---|
| 1 | NO DIFFICULTY | 5189 | 
                                    
                                    94.7%
                                 | 
| 2 | SOME DIFFICULTY | 135 | 
                                    
                                    2.5%
                                 | 
| 3 | A LOT OF DIFFICULTY | 25 | 
                                    
                                    0.5%
                                 | 
| 4 | CANNOT SEE AT ALL | 10 | 
                                    
                                    0.2%
                                 | 
| Sysmiss | 120 | 
                                    
                                    2.2%
                                 |