The main purpose of the HBS is to determine in detail the pattern of household expenditure in order to update the weighting basis of the Consumer Price Index. Since it is important not only to study the level of total expenditure, but also to learn the way in which expenditure varies with the income level of a particular household, in size, composition and other social characteristics, detailed particulars on these topics are also collected. The sampling frame is taken from all occupied private households from the Census of Population.