Year	% of total fuel combustion
1960	18.01281125078264
1961	18.11896807720861
1962	18.717066585376475
1963	18.800273831935648
1964	18.347683476834764
1965	18.68557210000395
1966	19.080827712358523
1967	19.518363756322852
1968	18.905855982067806
1969	18.17210221200246
1970	17.75075414781297
1971	33.50467796904508
1972	33.14762546546448
1973	32.573255975434755
1974	32.787859209006825
1975	33.61110922532773
1976	34.15211714709948
1977	34.680497258770295
1978	34.51647531684368
1979	33.594800537875386
1980	32.87914271520829
1981	31.858723635357215
1982	31.831789347635517
1983	31.57003384694339
1984	31.848853214197984
1985	29.995868151121808
1986	29.69198546438513
1987	29.70382812468072
1988	29.547159243352702
1989	28.958803114900277
1990	23.218352782353502
1991	22.853743647806528
1992	22.733632790567093
1993	22.232054843623985
1994	22.412920078705813
1995	24.373516794574222
1996	22.946652107034748
1997	22.854382845465885
1998	22.97478631040517
1999	21.434071577173256
2000	21.219077128623507
2001	21.099589661236536
2002	21.038983991364756
2003	21.044733589582307
2004	22.85666150394041
2005	23.75145175594791
2006	23.76433904511257
2007	24.53877888010671
2008	24.919082647073612
2009	25.20372515026389
2010	25.288729898683524
2011	25.292357229204598
2012	24.418286670700887
2013	24.246306177881383
2014	24.42522402732142