| Value | Category | Cases | |
|---|---|---|---|
| 1 | No-no difficulty | 70256 | 
                                    
                                    99.3%
                                 | 
| 2 | Yes-some difficulty | 195 | 
                                    
                                    0.3%
                                 | 
| 3 | Yes- a lot of difficulty | 185 | 
                                    
                                    0.3%
                                 | 
| 4 | can not do at all | 92 | 
                                    
                                    0.1%
                                 | 
| Sysmiss | 11050 |