Year	% of total fuel combustion
1971	18.75862068965517
1972	18.340611353711793
1973	15.730337078651685
1974	26.10966057441253
1975	12.133891213389122
1976	15.789473684210526
1977	11.143270622286542
1978	12.022630834512022
1979	12.393162393162394
1980	13.927227101631118
1981	11.320754716981133
1982	11.34020618556701
1983	10.861423220973784
1984	22.530120481927707
1985	28.776978417266186
1986	35.13266239707228
1987	48.541666666666664
1988	47.683535281539555
1989	48.854961832061065
1990	43.01538461538462
1991	48.60646599777035
1992	48.729281767955804
1993	48.350329934013196
1994	54.83247422680413
1995	49.370444002650764
1996	46.228373702422154
1997	44.544095665171895
1998	45.521292217327456
1999	38.61129136924075
2000	40.33107599699022
2001	50.99484156226971
2002	51.87908496732027
2003	46.75324675324675
2004	59.87460815047021
2005	58.81207400194742
2006	40.7949790794979
2007	35.34303534303534
2008	36.375838926174495
2009	38.44011142061281
2010	52.97941495124593
2011	54.290876242095756
2012	49.125874125874134
2013	57.6530612244898
2014	59.442993907745866