Consumer Price index is the most frequently used indicator of inflation and reflect changes in the cost of acquiring a fixed bask of goods and services by the average consumer. The weights are usually derived from household expenditure surveys. From 1995 the weight structure is based on the European National Accounting System Classification of Individual Consumtion by Purpose (COICOP). The consumer price index (CPI) is a measure of change over a specified period of time in the general level of prices of goods and services that a given population acquires, uses or pays for consumption. It compares a household's cost for a specific basket of finished goods and services with the cost of the same basket during an earlier benchmark period.