| Value | Category | Cases | |
|---|---|---|---|
| 1 | No difficulty | 3708 | 
                                                                 
                                    
                                    93.5%
                                 
                                                             | 
                                                        
                    
| 2 | Some difficulty | 229 | 
                                                                 
                                    
                                    5.8%
                                 
                                                             | 
                                                        
                    
| 3 | A lot of difficulty | 29 | 
                                                                 
                                    
                                    0.7%
                                 
                                                             | 
                                                        
                    
| 4 | Cannot see at all | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| 9 | No response | 1 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 362 |