Year	% of total fuel combustion
1960	0.9065944400556749
1961	1.0638685466535522
1962	1.0986048392532164
1963	1.22826607114372
1964	1.2124868044035577
1965	1.275200388632499
1966	1.4483840216488826
1967	1.5851277717882215
1968	1.7006230005051384
1969	1.5604337476857988
1970	1.801006011532328
1971	1.5665981427660018
1972	1.6757865937072458
1973	1.7840949830236812
1974	1.8844358744001595
1975	1.8985695708712582
1976	1.803806355447065
1977	1.9233340762201938
1978	2.0182152477872317
1979	1.9266441821247895
1980	2.045884059244935
1981	2.1890278357860593
1982	2.2747695704639397
1983	2.3139478893585164
1984	2.404604443952516
1985	2.4395791868069394
1986	2.5239364038298238
1987	2.5787965616045803
1988	2.6060878692457656
1989	2.85828846374155
1990	3.215629522431257
1991	3.065993138658527
1992	3.2015590200445434
1993	3.4387653306730845
1994	3.4089216007628353
1995	3.338766955813007
1996	3.260899808018699
1997	3.3226946312549877
1998	3.6978355443364292
1999	3.7627220388005145
2000	3.782745851049237
2001	3.83340578135188
2002	3.940397350993378
2003	3.922314274073066
2004	4.084564304106246
2005	5.631445386318233
2006	5.652065497464883
2007	5.798333616731848
2008	6.043420977258406
2009	5.065834857982665
2010	5.187014820042345
2011	4.867128362055082
2012	4.571703561116459
2013	4.30738183079494
2014	4.697563707644916