Year	% of total fuel combustion
1971	35.470966177718516
1972	37.048120660761306
1973	35.27256069628951
1974	32.92487402656894
1975	33.18075117370892
1976	33.191536997649166
1977	34.795698924731184
1978	32.66543918553017
1979	33.1965110312981
1980	32.08994431018178
1981	31.244014047036288
1982	30.482266435986162
1983	31.133868243243246
1984	29.301277235161532
1985	29.401709401709397
1986	35.873509590461374
1987	33.906852566004154
1988	39.53270151074412
1989	39.220555927022644
1990	34.51398671764942
1991	36.47384497899962
1992	35.385192831003096
1993	31.736861721953037
1994	28.25935596170583
1995	29.14997015943388
1996	30.25156224963948
1997	28.654434250764528
1998	29.144503546099287
1999	31.873653984206747
2000	32.299741602067186
2001	30.267039279614966
2002	30.096209193322913
2003	30.830976225059242
2004	31.938852112195455
2005	31.787459010908115
2006	31.699325814378426
2007	33.81651265325844
2008	34.452306821398246
2009	36.18759992893942
2010	35.88533271931844
2011	36.89148912683519
2012	38.49884153241015
2013	37.40251120084076
2014	38.03856348422639