Of the companies surveyed, 37 percent said sales rose in December, while 17 percent said sales were down. The resulting balance is + 20% below the retailer's forecast of + 30%, and below + 26% in November. Flash memory and DRAM demand growth over the long term Famous British economist hicks and others argue that the above theory did not consider the factor of income, and therefore unable to determine the level of interest rates, in 1937, and puts forward the is-lm model on the basis of general equilibrium theory. It establishes a theory of interest rates and income at the same time that the four factors of savings and investment, money supply and monetary demand interact. ECB President Mario draghi said at a press conference following the central bank's board meeting that important changes had taken place in the resumption of negotiations. The investment quantity is the decreasing function of interest rate, saving is the increment function of interest rate, and the change of interest rate depends on the equilibrium point of investment quantity and saving amount. Keynes's theory of money supply and demand decided that interest rates were a monetary factor rather than an actual factor. (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.