Year	% of total fuel combustion
1971	16.57544956997655
1972	20.57188244638602
1973	22.8110599078341
1974	22.324359816152334
1975	25.10795805058606
1976	27.42209631728046
1977	31.142857142857146
1978	35.69958847736625
1979	34.82060717571297
1980	34.233853946813
1981	32.26824457593688
1982	34.67620481927711
1983	35.00848896434635
1984	35.842771485676224
1985	38.78419452887539
1986	36.83884936591401
1987	35.2801660243107
1988	36.203028603477286
1989	35.51625239005736
1990	38.27384553337366
1991	44.151510095110964
1992	41.49443561208267
1993	44.00649542367878
1994	43.072495546114844
1995	43.63453562900591
1996	42.09483991638245
1997	43.19934203762722
1998	45.93100624424199
1999	45.75808878856284
2000	45.80544205859341
2001	45.54439000083049
2002	45.60765398908832
2003	46.01536607411872
2004	46.41053637232156
2005	48.37943649316475
2006	49.21184397601533
2007	48.472081788563074
2008	51.11157828349187
2009	54.12617070153737
2010	56.09756097560975
2011	57.70395905149901
2012	56.41357864731796
2013	54.42499043245312
2014	54.03591510974061