Year	% of total fuel combustion
1971	46.30872483221476
1972	47.05882352941176
1973	49.101796407185624
1974	47.826086956521735
1975	48.648648648648646
1976	47.16981132075471
1977	42.52873563218391
1978	43.40425531914894
1979	48.05194805194805
1980	48.61878453038674
1981	47.089947089947096
1982	45.45454545454545
1983	44.38775510204081
1984	46.927374301675975
1985	45.30386740331491
1986	42.72300469483569
1987	43.51851851851851
1988	42.70833333333333
1989	42.10526315789473
1990	40.21739130434782
1991	44.50549450549451
1992	43.39622641509434
1993	45.45454545454545
1994	42.25941422594142
1995	44.22310756972112
1996	43.98496240601503
1997	43.006993006993014
1998	39.88095238095239
1999	41.5929203539823
2000	40.96045197740113
2001	39.62264150943396
2002	39.947780678851174
2003	38.48101265822785
2004	35.60975609756098
2005	35.98014888337468
2006	35.14150943396226
2007	35.55045871559633
2008	36.0381861575179
2009	36.93045563549161
2010	37.38317757009346
2011	37.360178970917225
2012	40.18058690744921
2013	40.610328638497656
2014	41.62995594713656