| Value | Category | 
                                    
                    
                        | 0 | Cannot read at all | 
                                    
                    
                        | 1 | Able to read only parts of sentence | 
                                    
                    
                        | 2 | Able to read whole sentence | 
                                    
                    
                        | 3 | No card with required language | 
                                    
                    
                        | 4 | Vision problems | 
                            
            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.