| Value | Category | 
                                    
                    
                        | 0 |  | 
                                    
                    
                        | 1 | almost all | 
                                    
                    
                        | 2 | more than a half | 
                                    
                    
                        | 3 | a half of them | 
                                    
                    
                        | 4 | less thana half | 
                                    
                    
                        | 5 | a few of them | 
                            
            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.