Year	% of total fuel combustion
1971	11.565634539904055
1972	11.299864773495607
1973	12.990936555891238
1974	9.948370193419127
1975	10.165753717009322
1976	11.271826948136567
1977	11.156741957563312
1978	13.9956407020764
1979	18.04498657117278
1980	17.548212473215294
1981	15.648085963734049
1982	14.525361292150754
1983	14.21376608841634
1984	11.675242995997714
1985	14.799565391433633
1986	12.561111111111112
1987	14.77736008895007
1988	13.375303163217916
1989	4.166227746760771
1990	4.765016933040223
1991	4.840673111349803
1992	3.099273607748184
1993	2.228994340444058
1994	1.7532929868280527
1995	2.125488862438361
1996	1.5468607825295724
1997	2.4178212442271123
1998	2.3735489220563837
1999	1.2429105828405944
2000	1.3102968460111326
2001	1.0836252189141855
2002	0.9348878134623857
2003	0.8865979381443305
2004	1.2691979522184296
2005	1.4029786315562276
2006	1.1540075535039873
2007	1.535467128027682
2008	1.5890410958904115
2009	1.497353814379759
2010	1.5650080256821828
2011	1.9159456118665021
2012	2.1752957638977235
2013	2.057971014492753
2014	1.9953051643192488