instant passive profits Read more 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.  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. At present, there are 89, 92, 95 and other labels on the market, which represent the octane value of gasoline, which means the anti-detonation of gasoline, which has nothing to do with the cleaning of gasoline. The so-called "high label gasoline is cleaner" is misleading. It is more scientific, more economical, and can give full play to the engine's efficiency according to the engine compression ratio or the requirement of the automobile instruction manual. Charlotte Nelson, of Moneyfacts, said: "only 56 providers of SVR went up, seven of which raised their interest rates by less than 0.25 percentage points, resulting in a more modest rise in average SVR.