In order to maintain continuity in the time series data on wholesale price index, it is imperative to provide a linking factor so that the new series, when released, may be compared with the outgoing one. The Office of the Economic Adviser has been using the arithmetic conversion method to link the various prices index series. The linking factor for the three broad groups of commodities WPI are as follows. However, the detailed individual commodities indices and their weights are available from 2004-05 onwards.User may choose any other methods as may be considered appropriate.