Year	% of total fuel combustion
1960	7.014860139860141
1961	4.01615436392192
1962	3.4832172260924636
1963	4.031333588077951
1964	3.1628411350081334
1965	3.1208277703604805
1966	4.642694583522985
1967	4.106318637593506
1968	5.357142857142858
1969	9.773859716366424
1970	15.888588182228236
1971	12.594489148988053
1972	12.953494034575114
1973	10.271758649586975
1974	13.101464435146443
1975	8.315403113529932
1976	11.314378932649733
1977	12.079160130324604
1978	13.539651837524177
1979	14.587236168352694
1980	14.516349705842114
1981	11.893607374943329
1982	13.529606351306647
1983	14.48589626933576
1984	18.363569048500555
1985	23.299640226143566
1986	22.627005347593585
1987	22.651267022927083
1988	19.881252249010437
1989	18.495357210536287
1990	18.766807529773335
1991	22.49434815373022
1992	20.920201294033067
1993	21.444043321299638
1994	21.652719665271967
1995	20.555165144061842
1996	25.91346153846154
1997	21.222893707785285
1998	22.496067121132672
1999	20.762787381928355
2000	18.72233981142967
2001	20.488758553274682
2002	22.03679120045515
2003	23.934790663208595
2004	23.656530885446546
2005	22.754125076390306
2006	24.393906886934133
2007	21.925728263286633
2008	23.591057289240798
2009	25.47285679194301
2010	28.019113814074714
2011	24.328147100424328
2012	24.504321301474324
2013	24.58842272968667
2014	24.23837520042758