| Value | Category | Cases | |
|---|---|---|---|
| 1 | No-no difficulty | 60576 | 
                                                                 
                                    
                                    98%
                                 
                                                             | 
                                                        
                    
| 2 | Yes-some difficulty | 651 | 
                                                                 
                                    
                                    1.1%
                                 
                                                             | 
                                                        
                    
| 3 | Yes- a lot of difficulty | 499 | 
                                                                 
                                    
                                    0.8%
                                 
                                                             | 
                                                        
                    
| 4 | can not do at all | 80 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 8618 |