Evaluation of Coupling Coordination among the Urban Physical Environment, Economy, and Population: A Case Study of 36 Main Cities in China

Table 2

Economic indicator system and population indicator system.

Subsystem	First-level	Second-level	Description	Properties
Economy	Economic aggregates	GDP	The total market value of all final products and services produced within one year	Positive
		Fixed asset investment	The accumulation of physical assets such as machinery	Positive
		Total retail sales of consumer goods	The volume of physical transaction and the service revenue	Positive
		Per capita GDP	GDP divided by the household registered population	Positive
	Economic structure	Percentage of secondary industry in GDP	The added value of the secondary industry divided by GDP	Positive
		Actual utilization of foreign capital	The actually received foreign capital within one year	Positive
		Percentage of tertiary industry in GDP	The added value of the tertiary industry divided by GDP	Positive
	Economic growth	GDP growth rate	Annual growth rate of GDP calculated at comparable prices	Positive
	Economic benefit	Productivity of total industry employed persons	GDP divided by the number of total employees	Positive
		Per capital value-added of tertiary industry	The added value of the tertiary industry divided by the total population	Positive
Population		Total population	Household registered population	Positive
		Number of employees	The number of the population participating in economic activity	Positive