| Value | Category | 
                                    
                    
                        | -9 | -9. Don't know/Refused | 
                                    
                    
                        | -1 | -1. Missing | 
                                    
                    
                        | 1 | 1. Not at all well | 
                                    
                    
                        | 2 | 2. Not very well | 
                                    
                    
                        | 3 | 3. Fairly well | 
                                    
                    
                        | 4 | 4. Very well | 
                            
            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.