Year	% of total fuel combustion
1960	19.172690319851387
1961	19.413947217658936
1962	19.34073748359659
1963	19.191656056555424
1964	19.27107504358623
1965	18.930764844102217
1966	19.083919093386882
1967	19.200058452282807
1968	19.513929312304906
1969	19.36706366312367
1970	19.062479115671145
1971	19.47276189012546
1972	19.741617115184212
1973	19.796772786742267
1974	19.92731797594213
1975	21.0494744963391
1976	20.837336343726015
1977	21.11407791078492
1978	21.804277316319006
1979	21.487217696354772
1980	21.667302322734358
1981	22.08842555838215
1982	22.56885548828429
1983	22.96273077263119
1984	22.937317337366384
1985	22.959239701074445
1986	23.5708527263037
1987	23.874529419557163
1988	24.351526226005397
1989	24.60100975569382
1990	24.97298300926465
1991	24.9325699951303
1992	25.52080298546798
1993	25.79484529940144
1994	26.135807516574758
1995	26.353338995014205
1996	26.250343087047042
1997	26.304927819529016
1998	26.77015965838227
1999	27.353259971879297
2000	26.909994819351837
2001	27.024029545385687
2002	27.402933590999584
2003	27.279210773252657
2004	27.439074123990263
2005	27.549118493281213
2006	27.86978717968291
2007	27.790123304903588
2008	27.483775992729377
2009	28.121806816762522
2010	27.530355564401177
2011	27.667994199701813
2012	28.18902801097083
2013	28.204650180572717
2014	29.040211776556998