Year	% of total fuel combustion
1971	64.17445482866044
1972	63.929618768328446
1973	54.40528634361234
1974	59.250585480093676
1975	67.28971962616824
1976	49.84326018808778
1977	50.14749262536873
1978	67.20779220779221
1979	67.83439490445859
1980	61.85286103542234
1981	62.849162011173185
1982	69.83695652173913
1983	68.80000000000001
1984	68.46846846846846
1985	69.09547738693468
1986	66.07142857142857
1987	67.33333333333333
1988	72.8310502283105
1989	71.39240506329114
1990	74.85822306238185
1991	66.17336152219873
1992	70.42889390519188
1993	66.34304207119742
1994	64.92374727668846
1995	64.73317865429235
1996	64.63414634146342
1997	61.73570019723865
1998	64.5021645021645
1999	47.54420432220039
2000	48.17518248175182
2001	56.81063122923589
2002	52.41286863270778
2003	49.60732984293194
2004	49.9404052443385
2005	49.79716024340771
2006	48.25345247766044
2007	48.905660377358494
2008	53.69595536959554
2009	53.44709897610922
2010	58.98463593854375
2011	62.48216833095578
2012	61.9047619047619
2013	60.60606060606061
2014	59.220389805097454