| Value | Category | Cases | |
|---|---|---|---|
| 1 | Always available | 2880 | 
                                    
                                    57.5%
                                 | 
| 2 | Mostly available | 1579 | 
                                    
                                    31.5%
                                 | 
| 3 | Sometimes available | 432 | 
                                    
                                    8.6%
                                 | 
| 4 | Rarely available | 116 | 
                                    
                                    2.3%
                                 | 
| Sysmiss | 149 |