Year	% of total fuel combustion
1971	77.64227642276423
1972	65.89147286821705
1973	59.75232198142415
1974	49.25816023738872
1975	45.93495934959349
1976	43.32810047095761
1977	56.60377358490566
1978	53.38775510204081
1979	49.13733609385783
1980	36.47242455775234
1981	39.219888555507936
1982	35.71987480438185
1983	28.797083839611176
1984	40.715181932245926
1985	45.676586187535094
1986	50.17491254372813
1987	51.80913613749435
1988	49.94499449944994
1989	54.49297671733693
1990	51.339888181993445
1991	56.36517328825021
1992	52.290008841732984
1993	49.62241986910555
1994	51.761476284886385
1995	51.76622630672028
1996	51.8498143309036
1997	52.041748206131764
1998	50.18492539216937
1999	47.93449944175661
2000	42.16459977452086
2001	44.94163424124514
2002	39.983075946689226
2003	36.35719347980156
2004	32.25069054195638
2005	31.41931419314193
2006	29.612241349330553
2007	34.16834474426098
2008	35.37684325505189
2009	41.43537414965986
2010	41.73970345963756
2011	43.47744124670102
2012	41.56562683931725
2013	41.453853692281086
2014	36.92070911474662