Year	% of total fuel combustion
1971	29.239907867620317
1972	30.87143883169739
1973	30.08474576271187
1974	30.439761795693997
1975	29.718309859154928
1976	28.288368968991378
1977	29.29032258064516
1978	30.25018953752843
1979	31.062083119548483
1980	32.8149626983293
1981	33.32978610194743
1982	34.0181660899654
1983	33.34037162162162
1984	32.231404958677686
1985	29.948717948717952
1986	29.73561430793157
1987	29.002274300405418
1988	25.96415501548279
1989	26.44951762345974
1990	28.617428053934397
1991	28.598701794578083
1992	30.139814206624756
1993	33.29295564666418
1994	32.32375979112271
1995	32.65410520931025
1996	31.605511937189558
1997	31.03211009174312
1998	31.382978723404246
1999	29.504666188083274
2000	28.890324432960092
2001	28.380686228846457
2002	28.007565167338218
2003	26.733430165889455
2004	25.85818603698901
2005	26.514086863414306
2006	26.331044042593412
2007	25.644742405025067
2008	25.53637135578828
2009	24.018475750577366
2010	24.982730831222657
2011	27.18291202119439
2012	26.283743736192683
2013	25.283478068477237
2014	24.167143079881505