| Value | Category | Cases | |
|---|---|---|---|
| -999 | -999 | 5 | 
                                                                 
                                    
                                    1.6%
                                 
                                                             | 
                                                        
                    
| -888 | -888 | 80 | 
                                                                 
                                    
                                    26.1%
                                 
                                                             | 
                                                        
                    
| 1 | More than one month | 18 | 
                                                                 
                                    
                                    5.9%
                                 
                                                             | 
                                                        
                    
| 2 | Once every month | 12 | 
                                                                 
                                    
                                    3.9%
                                 
                                                             | 
                                                        
                    
| 3 | Once every two months | 19 | 
                                                                 
                                    
                                    6.2%
                                 
                                                             | 
                                                        
                    
| 4 | Once every three months | 86 | 
                                                                 
                                    
                                    28%
                                 
                                                             | 
                                                        
                    
| 5 | Less than once every three months | 87 | 
                                                                 
                                    
                                    28.3%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 605 |