| Value | Category | 
                                    
                    
                        | -9 | Don't know (spontaneous) | 
                                    
                    
                        | 1 | One day or less | 
                                    
                    
                        | 3 |  | 
                                    
                    
                        | 5 |  | 
                                    
                    
                        | 7 |  | 
                                    
                    
                        | 10 |  | 
                                    
                    
                        | 14 |  | 
                                    
                    
                        | 15 |  | 
                                    
                    
                        | 20 |  | 
                                    
                    
                        | 21 |  | 
                                    
                    
                        | 25 |  | 
                                    
                    
                        | 28 |  | 
                                    
                    
                        | 30 |  | 
                                    
                    
                        | 40 |  | 
                                    
                    
                        | 42 |  | 
                                    
                    
                        | 45 |  | 
                                    
                    
                        | 60 |  | 
                                    
                    
                        | 90 |  | 
                                    
                    
                        | 120 |  | 
                                    
                    
                        | 160 |  | 
                            
            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.