Compression ratio Interest rate, in the form of expression, refers to the ratio of the amount of interest to the total amount of borrowed capital in a certain period of time. [1] the interest rate is the interest level per unit time of the unit currency, indicating the interest rate. Economists have been looking for a theory that can fully explain the structure and change of interest rates. Interest rates are usually controlled by the central bank of the country and administered by the federal reserve board in the United States. Today, interest rates are one of the important tools for macroeconomic regulation. E CB staff predicted that the inflation rate would reach 1.4 PC by 2018, rising to 1.7 PC 2020 GDP growth of 2.3 PC next year - 0.5 percentage point upgrade - but will slow to 1.6 PC in 2020, it said.