Consumer Price Index is defined as a measure of the weighted aggregate change inretail prices paid by consumers for a given basket of goods and services. Pricechanges are measured by re-pricing the same basket of goods and services atregular intervals, and comparing aggregate costs with the costs of the samebasket in a selected base period Price data for constructing the indices arecollected by Kenya National Bureau of Statistics through a survey of retailprices for consumption goods and services. The percentage change of the CPI overa one-year period is what is usually referred to as inflation.