Year	% of total fuel combustion
1960	19.7376267143709
1961	19.68312004875076
1962	21.64058283864004
1963	16.21488417939872
1964	21.672661870503596
1965	22.81964436917866
1966	24.844036697247702
1967	22.718052738336713
1968	23.26748196926936
1969	26.795895096921324
1970	26.2936695560809
1971	30.412135611806633
1972	29.871000167532245
1973	29.933285105698896
1974	31.43525741029641
1975	31.378833126957538
1976	31.034244206157037
1977	32.81964215750295
1978	35.5466768138001
1979	36.20623562484028
1980	34.4819144378481
1981	35.632038466405156
1982	35.54473889790277
1983	35.03649635036496
1984	35.300527643955036
1985	37.83051582141309
1986	40.93023255813954
1987	37.99084088473156
1988	35.718949324494
1989	38.716277299329114
1990	53.26321629422987
1991	53.94004207668084
1992	56.098896221110884
1993	56.45957923095443
1994	58.493129001027064
1995	56.71372773173287
1996	57.81785385142534
1997	57.31478671527809
1998	57.545366521427034
1999	57.43701742590961
2000	57.607355450856154
2001	57.763819611224
2002	57.84280616666599
2003	57.89965879922369
2004	56.826889858986824
2005	57.85772960055968
2006	58.43795367869957
2007	56.67586491850693
2008	55.86005767609481
2009	56.7532493146362
2010	57.05410844088691
2011	57.255798666209586
2012	58.011978111939335
2013	57.498933178689846
2014	56.8524156187955