Year	% of total fuel combustion
1960	2.613774946357375
1961	2.554161047548614
1962	2.671868188295542
1963	2.7138108189785437
1964	2.5783836171632117
1965	2.7340823970037453
1966	2.7463546354635473
1967	2.6477672268209638
1968	2.767665196855336
1969	2.7334733592109073
1970	2.0043638911893993
1971	2.651844893051446
1972	2.5871038011517657
1973	2.6332571047657956
1974	2.6502686788129117
1975	2.8501383769461164
1976	2.733190594606011
1977	2.6405171880245537
1978	2.7494489169356178
1979	2.9529699176951008
1980	2.7672009044851102
1981	2.782265353693924
1982	2.611226643902833
1983	2.7310128081618466
1984	2.292519595597856
1985	2.3817441104823716
1986	2.3711250418901604
1987	2.396352777857312
1988	2.3113871450593155
1989	2.081102258794951
1990	1.8276047056910372
1991	1.8539843593839274
1992	1.6345767443827954
1993	1.6351950784322462
1994	1.6127964225055356
1995	1.642148390638661
1996	1.6092212640233077
1997	1.5721415479135614
1998	1.5017149013079978
1999	1.4374682011682656
2000	1.4131941996286634
2001	1.4136332048377498
2002	1.398295503278778
2003	1.2827898230579329
2004	1.3557001286027692
2005	1.4123499806718367
2006	1.4123759537509284
2007	1.3298249648690261
2008	1.3132986455916524
2009	1.3046953853607335
2010	1.316159522748843
2011	1.2590767502625853
2012	1.2562082589027899
2013	1.2637338810459628
2014	1.2348481228397128