| Value | Category | Cases | |
|---|---|---|---|
| 1 | No difficulty | 2603835 | 
                                    
                                    96.4%
                                 | 
| 2 | Yes, some difficulty | 72295 | 
                                    
                                    2.7%
                                 | 
| 3 | Yes, a lot of difficulty | 21515 | 
                                    
                                    0.8%
                                 | 
| 4 | Cannot do at all | 3400 | 
                                    
                                    0.1%
                                 | 
| Sysmiss | 383938 |