Year	% of total fuel combustion
1971	28.96607869742198
1972	28.67904786816636
1973	30.093056549749466
1974	28.89527606508738
1975	27.78018173950671
1976	29.36926698595665
1977	30.102748104052843
1978	32.32318710832587
1979	33.18669716698926
1980	33.3723408701467
1981	33.13816863822838
1982	30.043948889069746
1983	26.903255541123734
1984	25.504718671604348
1985	25.83638774077829
1986	25.544670846394983
1987	24.35008032715058
1988	25.020001454651247
1989	23.42949292241533
1990	22.998202185036643
1991	21.331040050545827
1992	19.29276432578286
1993	16.111633086265094
1994	15.552747515453706
1995	15.183486238532113
1996	16.01231472371219
1997	16.471300923822508
1998	16.777987941837093
1999	15.65343450232874
2000	15.302631180549248
2001	12.697550643567043
2002	13.258693361433089
2003	13.019286908355994
2004	13.6295128341874
2005	14.711821916854298
2006	14.011459355810715
2007	12.199323955948097
2008	11.325804424078994
2009	15.43527822342312
2010	13.713097541894845
2011	12.59557092560572
2012	12.27097396335583
2013	12.691466083150985
2014	13.032239004394551