| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 | 
                                    
                                    6.3%
                                 | 
| -7 | Does not apply | 0 | 
                                    
                                    0%
                                 | 
| 0 | No obstacle | 37 | 
                                    
                                    33.3%
                                 | 
| 1 | Minor obstacle | 39 | 
                                    
                                    35.1%
                                 | 
| 2 | Moderate obstacle | 16 | 
                                    
                                    14.4%
                                 | 
| 3 | Major obstacle | 9 | 
                                    
                                    8.1%
                                 | 
| 4 | Very severe obstacle | 3 | 
                                    
                                    2.7%
                                 |