| Value | Category | Cases | |
|---|---|---|---|
| 1 | less than 12 months | 9 | 
                                                                 
                                    
                                    20.9%
                                 
                                                             | 
                                                        
                    
| 2 | 12-23 months | 4 | 
                                                                 
                                    
                                    9.3%
                                 
                                                             | 
                                                        
                    
| 3 | 2 years or more | 30 | 
                                                                 
                                    
                                    69.8%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 169 |