Base year - the price indices start from a selected base year, which is given the value of 100. The price changes in subsequent periods are evaluated in relation to the base year.

For example: assume the base year is 2006 (2006=100). In the first quarter of 2008, the price index is 105.3. This means that the prices of goods and/or services included in the price index have increased by 5.3% from base year 2006 to the first quarter of 2008.