Table 3.

Descriptive statistics of input and output variables

Variable name	Unit	Min	Max	Mean	Std
Oil	Exajoules	0.46	28.5	9.51	8.37
Natural gas		0.04	11.9	2.08	3.04
Coal		4.52	82.49	34.63	27.89
Hydroelectricity		0.19	11.74	3.09	3.53
Primary energy		5.39	145.46	50.48	44.31
CO2 emissions	Mt	475.9	9893.5	3896.16	3200.44