Research on the Change Rule of the Proportion of the Added Value of Circulation Industry in GDP -- Based on nonlinear regression model and logarithmic model

Nonlinear regression model means that the relationship between variables is not linear, but it can be transformed into linear regression model through variable replacement; logarithmic model means that both sides of the equation take logarithm, which is conducive to reducing the heteroscedasticity of data in the model. Based on this model, this paper empirically analyzes the change law of the proportion of added value of circulation industry in GDP. The results of the study show that the change trend of the proportion of circulation industry added value to GDP does not present a single linear relationship, but a "inverted U-shaped" development law. In recent years, the market demand for circulation has been increasing, and the status and value of the circulation industry in the economic development are expending. The traditional circulation industry needs to be transformed and upgraded. Therefore, it is of great significance to study the development law of the added value of circulation industry in GDP for the construction of modern circulation system in China.