<P> At any one time there might be two or three units of account in one region based on the local base, silver and sometimes gold coins, and each often expressed in L.S.D units in ratio 240: 12: 1 . The Florentine gold florin, the French franc and the electoral rheingulden all became pounds (240 denari) of account . Units of account would often survive over 100 years despite the original coins changing composition and availability (e.g. the Castilian maravedi). </P> <P> A modern unit of account is the European Currency Unit, used in the European Union from 1979 to 1998; its replacement in 1999, the euro, was also just a unit of account until the introduction of notes and coins in 2002 . </P> <P> Unit of account is the main way of calculating a carrier or ship owner's liability in relation to carriage of goods contracts in which the Hague - Visby Rules apply . </P> <P> In economics, a standard unit of account is used for statistical purposes to describe economic activity . Indexes such as GDP and the CPI are so broad in their scope that compiling them would be impossible without a standard unit of account . After being compiled, these figures are often used to guide governmental policy; especially monetary and fiscal policy . </P>

Explain the significance of the unit of account function of money