  The effective medium approximation (EMA) method is commonly used to estimate
the effective conductivity development in composites containing two types of
materials: conductors and insulators. The effective conductivity is a global
parameter that measures how easily the composite conducts electric current.
Currently, financial transactions in society take place in cash or cashless,
and, in the cashless transactions the money flows faster than in the cash
transactions. Therefore, to provide a cashless grading of countries, we
introduce a cashless transaction index (CTI) which is calculated using the EMA
method in which individuals who make cash transactions are analogous to the
insulator element in the composite and individuals who make cash transactions
are analogous to the conductor element. We define the CTI as the logarithmic of
the effective conductivity of a country's transactions. We also introduce the
time dependent equation for the cashless share. Estimates from the proposed
model can explain well the data in the last few years.
