Table 4. Coupling degree of the study area.

City/Year	2000	2002	2004	2006	2008	2010	2012	2014	2016
Dongying	0.806	0.901	0.969	0.979	0.995	0.999	0.992	0.980	0.974
Binzhou	0.965	0.978	0.998	0.999	0.999	0.998	0.999	0.995	0.993
Dongying and Binzhou	0.847	0.899	0.978	0.989	0.990	0.995	0.998	0.996	0.974