| Value | Category | 
                                    
                    
                        | 1 | Kilogram | 
                                    
                    
                        | 2 | Gram | 
                                    
                    
                        | 3 | Number | 
                                    
                    
                        | 4 | Litres | 
                                    
                    
                        | 5 | Millitres | 
                                    
                    
                        | 6 | Metres | 
                                    
                    
                        | 7 | Cubic metres | 
                                    
                    
                        | 8 | Packet | 
                                    
                    
                        | 9 | Kwh (electricity measurement) | 
                                    
                    
                        | 10 | Other (specify) | 
                                    
                    
                        | 99 | NS | 
                            
            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.