| Value | Category | Cases | |
|---|---|---|---|
| 1 | NO DIFFICULTY | 4561 | 
                                    
                                    83.2%
                                 | 
| 2 | SOME DIFFICULTY | 681 | 
                                    
                                    12.4%
                                 | 
| 3 | A LOT OF DIFFICULTY | 97 | 
                                    
                                    1.8%
                                 | 
| 4 | CANNOT SEE AT ALL | 18 | 
                                    
                                    0.3%
                                 | 
| 9 | NO RESPONSE | 2 | 
                                    
                                    0%
                                 | 
| Sysmiss | 120 | 
                                    
                                    2.2%
                                 |