| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                                                 
                                    
                                    0.2%
                                 
                                                             | 
                                                        
                    
| -7 | Does not apply | 30 | 
                                                                 
                                    
                                    5.2%
                                 
                                                             | 
                                                        
                    
| 0 | No obstacle | 458 | 
                                                                 
                                    
                                    79%
                                 
                                                             | 
                                                        
                    
| 1 | Minor obstacle | 26 | 
                                                                 
                                    
                                    4.5%
                                 
                                                             | 
                                                        
                    
| 2 | Moderate obstacle | 31 | 
                                                                 
                                    
                                    5.3%
                                 
                                                             | 
                                                        
                    
| 3 | Major obstacle | 21 | 
                                                                 
                                    
                                    3.6%
                                 
                                                             | 
                                                        
                    
| 4 | Very severe obstacle | 13 | 
                                                                 
                                    
                                    2.2%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 1 |