Year	% of total fuel combustion
1971	22.500000000000004
1972	20.75471698113208
1973	29.15129151291513
1974	24.911032028469748
1975	22.697368421052634
1976	27.586206896551722
1977	33.724340175953074
1978	36.68341708542713
1979	31.23287671232877
1980	19.469026548672566
1981	13.712374581939798
1982	16.89189189189189
1983	32.887700534759354
1984	44.91017964071857
1985	32.786885245901644
1986	33.116883116883116
1987	32.786885245901644
1988	29.411764705882348
1989	23.20819112627986
1990	22.22222222222222
1991	22.58064516129032
1992	24.909747292418775
1993	30.743243243243246
1994	34.3042071197411
1995	31.28834355828221
1996	38.50129198966409
1997	44.56066945606694
1998	51.13871635610765
1999	37.369207772795214
2000	37.44075829383887
2001	39.29712460063898
2002	41.379310344827594
2003	42.33009708737864
2004	42.988929889298895
2005	53.87263339070568
2006	41.56305506216696
2007	44.14414414414415
2008	44.65408805031446
2009	42.567567567567565
2010	46.85990338164251
2011	47.781569965870304
2012	46.192893401015226
2013	41.782407407407405
2014	42.032085561497325