How and When Factors of Agricultural Contribution Influence Urbanization: A Historical Analysis of Tibet

Table 1

Index systems of independent variables for the econometric model.

ACFs	Descriptions	Unit	Direction
FDC	X11: Urban food consumption per year	t	+
	X12: Quantity of surplus agricultural products per year	t	+
	X13: Power of farm machinery	kWh	+
	X14: Grain yield per hectare	kg	+
MLC	X21: Total value of agricultural-product-processing industry	10,000 ¥	+
	X22: Ratio of total value of agricultural-product-processing industry to total value of industry	%	+
	X23: Ratio of agricultural commodities by value	%	+
LRC	X31: Agricultural labor input per unit of agricultural-product value	Person/100,000¥	−
	X32: Ratio of rural residents employed in agriculture	%	−
	X33: Ratio of rural residents employed in nonagricultural sectors	%	+
MTC	X41: per capita savings deposit of urban and rural residents	¥	+
	X42: per capita rural expenditure	¥	+
	X43: Rural retail sales of consumer goods	10,000 ¥	+