Table 2 Description of control variables.
Control variables | Description |
|---|---|
Economic development level (GDP) | Gross regional industry (100 million yuan) |
Technological progress (tps) | Technological market turnover (10,000 yuan) |
Energy consumption structure (ecs) | The proportion of coal consumption in energy consumption (%) |
State-owned economic development (sed) | The proportion of state-owned economic income in the total GDP (%) |
Opening to the outside world (oul) | The proportion of foreign investment in the total GDP (%) |
Industrial structure level (isl) | The proportion of the added value of the secondary industry in the total value (%) |
Population density (pd) | The number of people living per square kilometer of land (square kilometers) |
