**Appendix A**


**Table A1.** Statistics of the 42 countries over the period of 2008–2011.

**Table A2.** Statistics of the 42 countries over the period of 2012–2017.


**Table A3.** Case Processing Summary.



**Table A4.** Person's correlation over the period of 2008–2012.

**Table A5.** Person's correlation over the period of 2013–2017.


*Energies* **2018**, *11*, 3037
