| Value | Category | Cases | |
|---|---|---|---|
| 1 | flat | 348 | 
                                                                 
                                    
                                    52.2%
                                 
                                                             | 
                                                        
                    
| 2 | slightly sloped | 258 | 
                                                                 
                                    
                                    38.7%
                                 
                                                             | 
                                                        
                    
| 3 | very steep | 61 | 
                                                                 
                                    
                                    9.1%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 1115 |