| Value | Category | Cases | |
|---|---|---|---|
| 1 | flat | 49 | 
                                                                 
                                    
                                    57%
                                 
                                                             | 
                                                        
                    
| 2 | slightly sloped | 33 | 
                                                                 
                                    
                                    38.4%
                                 
                                                             | 
                                                        
                    
| 3 | very steep | 4 | 
                                                                 
                                    
                                    4.7%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 1696 |