fig5

Figure 5. (A) Relationship between biomass and per capita income based on second-degree polynomial analysis; (B) Relationship between metal ores and per capita income based on second-degree polynomial analysis; (C) Relationship between non-metallic minerals and per capita income based on second-degree polynomial analysis; (D) Relationship between fossil fuels and per capita income based on second-degree polynomial analysis. DMC: Domestic material consumption; GDPPC: gross domestic product per capita.