Year	% of total fuel combustion
1971	26.203630623520123
1972	27.411519777931993
1973	24.77220956719818
1974	24.356435643564357
1975	26.78809418036428
1976	27.683397683397686
1977	31.77461516119663
1978	35.16941131932614
1979	30.29068187992393
1980	19.696207624987423
1981	22.567507746790614
1982	23.618090452261306
1983	30.51249721871987
1984	39.92836431860822
1985	37.42570894888775
1986	34.053689008948176
1987	34.89283244987325
1988	34.47054571738345
1989	32.635316281428885
1990	32.691289383108284
1991	32.72079862656578
1992	31.954049935529248
1993	31.76060622822059
1994	31.72513862258382
1995	28.243398392652118
1996	27.94240503218831
1997	28.058148580318942
1998	26.29786074397057
1999	25.70430321524921
2000	25.975188643048984
2001	26.317998656816656
2002	26.012692940531224
2003	25.789612047921285
2004	25.585023400936034
2005	25.41951939857699
2006	25.852102220677892
2007	27.391173821675167
2008	27.05129613356766
2009	26.76067474960464
2010	25.144356955380577
2011	25.370489690721648
2012	25.985237622480255
2013	26.437245244565215
2014	25.918395546694565