Year	% of total fuel combustion
1971	27.77777777777778
1972	27.77777777777778
1973	34.017595307917894
1974	28.020565552699228
1975	23.12925170068027
1976	22.863247863247864
1977	25.208333333333332
1978	27.360308285163775
1979	27.368421052631575
1980	26.595744680851062
1981	26.21664050235479
1982	28.924418604651166
1983	30.48211508553655
1984	33.17683881064163
1985	39.090909090909086
1986	40.610328638497656
1987	39.361702127659576
1988	43.23770491803279
1989	40.038131553860815
1990	38.96672504378283
1991	42.7906976744186
1992	44.29301533219761
1993	46.27702161729383
1994	45.28582034149962
1995	40.77669902912621
1996	40.3119376124775
1997	38.26040554962647
1998	41.1702688455456
1999	44.73817996949669
2000	43.0276981852913
2001	43.15619967793881
2002	43.40617935192162
2003	41.705649514213746
2004	45.879582912882604
2005	46.22848200312989
2006	48.33759590792839
2007	48.47184986595175
2008	48.37288965011011
2009	48.60322507381331
2010	48.64593781344032
2011	47.44744744744745
2012	49.26701570680629
2013	52.11409395973155
2014	52.80231251003694