| Value | Category | 
                                    
                    
                        | -9 | break-off | 
                                    
                    
                        | -3 | interviewer error | 
                                    
                    
                        | 10 |  | 
                                    
                    
                        | 11 |  | 
                                    
                    
                        | 12 |  | 
                                    
                    
                        | 13 |  | 
                                    
                    
                        | 14 |  | 
                                    
                    
                        | 15 |  | 
                                    
                    
                        | 16 |  | 
                                    
                    
                        | 17 |  | 
                                    
                    
                        | 18 |  | 
                                    
                    
                        | 19 |  | 
                                    
                    
                        | 20 |  | 
                                    
                    
                        | 21 |  | 
                                    
                    
                        | 22 |  | 
                                    
                    
                        | Sysmiss |  | 
                            
            Warning: these figures indicate the number of cases found in the data file. They cannot be interpreted as summary statistics of the population of interest.