| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 | 
                                    
                                    11%
                                 | 
| 2011 | 1 | 
                                    
                                    1%
                                 | |
| 2014 | 1 | 
                                    
                                    1%
                                 | |
| 2017 | 2 | 
                                    
                                    2%
                                 | |
| 2018 | 4 | 
                                    
                                    4%
                                 | |
| 2019 | 3 | 
                                    
                                    3%
                                 | |
| 2020 | 5 | 
                                    
                                    5%
                                 | |
| 2021 | 13 | 
                                    
                                    13%
                                 | |
| 2022 | 20 | 
                                    
                                    20%
                                 | |
| 2023 | 26 | 
                                    
                                    26%
                                 | |
| 2024 | 13 | 
                                    
                                    13%
                                 | |
| 2025 | 1 | 
                                    
                                    1%
                                 | |
| Sysmiss | 115 |