Year	% of total fuel combustion
1960	27.747886241352802
1961	29.291338582677167
1962	29.50693374422188
1963	28.691392582225333
1964	29.594594594594593
1965	29.364089775561098
1966	28.871681415929206
1967	29.712112982074956
1968	29.677088672475648
1969	28.44669117647059
1970	28.153717627401836
1971	29.708568943018705
1972	29.68152866242038
1973	28.89554794520548
1974	30.05729396209784
1975	33.85593220338983
1976	29.952644041041832
1977	31.15124153498871
1978	31.27769571639587
1979	32.3723515109413
1980	31.178846860080796
1981	32.05027494108405
1982	34.046052631578945
1983	34.83606557377049
1984	35.409181636726544
1985	35.02461188943582
1986	33.82699427802087
1987	36.996735582154514
1988	37.39632167327803
1989	38.9811738648948
1990	36.52585579024035
1991	39.113680154142585
1992	36.04852686308492
1993	36.04193971166448
1994	33.758953597010276
1995	36.68789808917198
1996	37.20642768850432
1997	35.88390501319261
1998	35.44055944055944
1999	34.614350980919106
2000	37.80985252588642
2001	37.28710462287104
2002	37.72307692307692
2003	36.02395892755277
2004	36.565486228218106
2005	37.89504204117135
2006	38.58956276445698
2007	39.60588398556758
2008	39.43342776203966
2009	38.21138211382114
2010	37.759446514103246
2011	37.80049737496547
2012	37.77526821005082
2013	39.686609686609685
2014	39.762107051826675