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. According to data released on Wednesday by the U.S. energy information administration (EIA), the number of commercial crude stocks removed from strategic reserves fell by 649.5 million barrels to 465 million barrels, by 1.5 percent, while the previous value fell by 5.11 million barrels. (3) monetary benefits -- increase the monetary value of assets. There are both measurable and unquantifiable benefits in these three different forms of income. Among them: mental income is too strong to measure, monetary gain is easy to measure because of the static concept of value change. Economists, therefore, focus only on actual earnings. That does not stop Mr Draghi from warning that inflation is still being affected by a sluggish wage growth, which is now much slower than the "post-recession recovery".