Prediction of China’s Sulfur Dioxide Emissions by Discrete Grey Model with Fractional Order Generation Operators

Table 5

Fitting accuracy of China’s sulfur dioxide emissions (unit: million tons).

	Year				Fractional order
						(%)		(%)		(%)		(%)
			1	2007	24.681
2	2008	23.212	23.021	0.824	23.024	0.811	23.246	0.147	23.21	0.007
3	2009	22.144	22.532	1.752	22.534	1.762	22.299	0.701	22.387	1.097
4	2010	21.851	22.054	0.927	22.055	0.933	21.674	0.808	21.862	0.050
5	2011	22.179	21.585	2.676	21.586	2.675	21.262	4.134	21.478	3.161
6	2012	21.176	21.127	0.231	21.127	0.233	20.99	0.878	21.177	0.003
7	2013	20.440	20.679	1.167	20.677	1.161	20.811	1.813	20.929	2.392
Average relative error			1.263%		1.262%		1.413%		1.118%