| Value | Category | Cases | |
|---|---|---|---|
| -1 | Missing | 0 | 
                                    
                                    0%
                                 | 
| 1 | Human Activity | 211 | 
                                    
                                    17.6%
                                 | 
| 2 | Natural processes | 443 | 
                                    
                                    36.9%
                                 | 
| 3 | Both human activity and natural processes | 86 | 
                                    
                                    7.2%
                                 | 
| 4 | None of these | 7 | 
                                    
                                    0.6%
                                 | 
| 7 | Not applicable | 449 | 
                                    
                                    37.4%
                                 | 
| 8 | Refused | 0 | 
                                    
                                    0%
                                 | 
| 9 | Don’t know / Haven’t heard enough | 4 | 
                                    
                                    0.3%
                                 |