| Value | Category | Cases | |
|---|---|---|---|
| 2016 | 1 | 
                                    
                                    0.1%
                                 | |
| 2017 | 50 | 
                                    
                                    3.2%
                                 | |
| 2018 | 197 | 
                                    
                                    12.6%
                                 | |
| 2019 | 9 | 
                                    
                                    0.6%
                                 | |
| 9999 | NO RESPONSE | 1 | 
                                    
                                    0.1%
                                 | 
| Sysmiss | 1306 | 
                                    
                                    83.5%
                                 |