The accounting income maintains the financial capital preservation, namely, the monetary value that only requires the owner to invest is not eroded, the enterprise income exceeds the input value part is the accounting income. Accounting focuses on reporting financial results. The economic benefits insist on physical capital preservation, which can only be confirmed when the actual production capacity of the owner is saved. It is believed that only by maintaining the actual production capacity of the enterprise can the enterprise reproduce smoothly. Physical capital preservation is more meaningful than the income of financial capital preservation, but it is difficult to measure. In November 2017, Advisor Perspectives published an article said that in addition to the improvement of fuel efficiency, petrol consumption decline is due in large part to the following factors: the ageing staff away from the workplace; The home office model is developing more and more; Social media takes the place of face-to-face communication, and travel is unnecessary. More and more young people are no longer driving their cars. And urban population growth accelerated, reducing per capita gasoline dependence. The ECB confirmed that it plans to slow its bond-buying efforts to 30 billion euros (22 billion pounds) by the end of September 2018, from January 2018.