Year	% of total fuel combustion
1971	24.0411538711988
1972	26.1950036063209
1973	27.8372591006424
1974	28.686814296291306
1975	29.33703082677673
1976	30.046273136568292
1977	29.764504515138995
1978	32.08413926499033
1979	28.51265641963317
1980	34.027364663890545
1981	34.64114265394417
1982	35.565927654609105
1983	35.20449542347352
1984	34.91158014831717
1985	33.95667046750285
1986	33.244013683010266
1987	30.695987304466104
1988	31.157870397132783
1989	34.163442940038685
1990	45.050558807876534
1991	48.43818420668514
1992	48.90726969191076
1993	50.62839410395655
1994	53.058727569331154
1995	55.90525632706035
1996	57.235628958550464
1997	57.65002849930787
1998	57.80742260988541
1999	57.29081493594986
2000	57.46311711860217
2001	57.917319910883734
2002	58.565091281351314
2003	57.24995880705224
2004	57.104183757178006
2005	57.15009285834881
2006	56.87741718513536
2007	60.11713272292337
2008	58.73371862330716
2009	57.66798056650472
2010	60.606604450825564
2011	61.22984966491577
2012	60.96337654963566
2013	59.20727488385885
2014	58.59140341791817