Year	% of total fuel combustion
1960	32.91592128801431
1961	33.94271785496649
1962	33.027522935779814
1963	31.789058649581076
1964	32.05935251798561
1965	33.19220999153259
1966	32.80733944954128
1967	30.493576741041245
1968	29.570398243963623
1969	26.68187001140251
1970	26.976622012083006
1971	17.535195425510214
1972	17.69285626460101
1973	17.9758083965642
1974	18.198355267547
1975	17.67015548673671
1976	17.450325959134275
1977	16.97996615382454
1978	16.844272894834194
1979	16.85963760215415
1980	17.02523495251421
1981	17.28514882211019
1982	16.80028546943049
1983	16.36787000868971
1984	15.880771596428344
1985	15.983571666283993
1986	15.912191553305918
1987	15.620842365769471
1988	15.536195166891076
1989	15.754016017284714
1990	13.96554587950549
1991	14.166903635987039
1992	14.280736098837913
1993	14.195839072816227
1994	14.125924047529484
1995	14.04083247005746
1996	15.05493639394746
1997	14.910895581517932
1998	15.095928309376315
1999	15.406351707378322
2000	15.931084018967583
2001	15.857313683164318
2002	15.848065235634028
2003	15.397470908425749
2004	15.388675415805055
2005	14.868414046960416
2006	14.46457816049448
2007	14.411178564917362
2008	14.810324145136535
2009	14.655915738740786
2010	14.567609640219036
2011	14.442630293915597
2012	14.879886342600745
2013	15.085191227116185
2014	15.18044608573134