Year	% of total fuel combustion
1971	2.9982812400534717
1972	2.922576287836926
1973	2.6955839497870433
1974	2.6119805720453306
1975	2.4141498743656684
1976	2.3475694124158295
1977	2.287581699346405
1978	2.5269645608628664
1979	1.4692563147831343
1980	1.4636721374412134
1981	1.4446520530465294
1982	1.337777160579549
1983	1.3462832964708147
1984	1.361532177543796
1985	1.3457139012245996
1986	1.3123718386876282
1987	1.256870180222402
1988	1.3450993831391365
1989	1.300510915002322
1990	1.2386186531047494
1991	1.3029998324115968
1992	1.2872801427478973
1993	1.9644180874722017
1994	2.0432014185540424
1995	2.1636188642925895
1996	2.0698864900957057
1997	1.8167734666572783
1998	1.5138541630989486
1999	1.469408590388682
2000	1.3083312537877434
2001	1.2070654406420824
2002	1.1933174224343681
2003	1.1256281407035176
2004	1.0334816077564397
2005	0.9616159445593492
2006	1.1070702748957109
2007	1.1393827917433066
2008	1.1412773800241016
2009	1.1917280056081312
2010	1.4603923882578551
2011	2.4204790267393235
2012	2.607373249282544
2013	2.504015874515733
2014	2.4167181105242705