Year	% of total fuel combustion
1960	1.9081812203401882
1961	1.8919701635916695
1962	1.8296134356940699
1963	1.7053062256645355
1964	1.545385125746404
1965	1.4923061803692195
1966	1.3687505287200756
1967	1.2161223071577503
1968	1.2215961573988556
1969	1.1522694903709203
1970	1.099259518367869
1971	1.8157268154353108
1972	1.6713091922005578
1973	1.5807933817336712
1974	1.8074505561810013
1975	1.972229429823856
1976	1.7821241637491751
1977	1.4861933578347806
1978	1.4875842478748058
1979	1.7994103368164427
1980	1.2935996848700637
1981	1.3119028658029463
1982	1.263077492824739
1983	1.4567278469073344
1984	1.414078351802715
1985	1.54664185304576
1986	1.5015310122101304
1987	1.405115319189355
1988	1.388461435184134
1989	1.3389479694525728
1990	1.3809618007475357
1991	1.3439241157151396
1992	0.9788923115089623
1993	0.9083070312010935
1994	0.9107341213754755
1995	0.9025896971918986
1996	0.8973608832493907
1997	0.8781552624459373
1998	0.8040657583222847
1999	0.7586846034466287
2000	0.7856251683609088
2001	0.8486853138369433
2002	0.9089841668397806
2003	0.8034799040887093
2004	0.9847392665002295
2005	0.9634759490518692
2006	1.0721821745696807
2007	0.9810301344035913
2008	0.971765107173572
2009	0.9775638834579787
2010	0.9599685808062397
2011	0.894824105559692
2012	0.9317763975155279
2013	0.9717489325262538
2014	0.9439338821261113