| Value | Category | Cases | |
|---|---|---|---|
| -99 | 1 | 
                                    
                                    0.3%
                                 | |
| 1 | Hanoi | 230 | 
                                    
                                    61.8%
                                 | 
| 2 | Ho Chi Minh City | 38 | 
                                    
                                    10.2%
                                 | 
| 3 | Northern region | 19 | 
                                    
                                    5.1%
                                 | 
| 4 | Central region | 60 | 
                                    
                                    16.1%
                                 | 
| 5 | Southern region | 5 | 
                                    
                                    1.3%
                                 | 
| 6 | Mekong Delta region | 19 | 
                                    
                                    5.1%
                                 | 
| Sysmiss | 57 |