Year	% of total fuel combustion
1971	47.88732394366197
1972	50.418410041841
1973	55.140186915887845
1974	46.09090909090909
1975	50.78053259871441
1976	49.047619047619044
1977	48.04123711340206
1978	49.61139896373057
1979	56.76243868255081
1980	61.78082191780822
1981	61.66032953105197
1982	58.66900175131349
1983	65.08179959100205
1984	66.29107981220656
1985	70.76233183856502
1986	69.35866983372921
1987	71.57780979827089
1988	69.56802063185042
1989	71.36237256719185
1990	73.42342342342343
1991	74.90336830480398
1992	71.72312223858614
1993	73.18823801805974
1994	64.70911086717892
1995	66.70317634173055
1996	67.64121487368719
1997	64.92673992673993
1998	57.01182717837317
1999	48.24561403508772
2000	56.19732275656916
2001	57.28764478764479
2002	63.06081754735793
2003	67.15720626021957
2004	69.17624052798827
2005	71.52189692717155
2006	69.99054820415878
2007	69.77061094708154
2008	68.3313885647608
2009	65.05190311418684
2010	67.08740176232436
2011	66.84925503943909
2012	66.44488800177423
2013	66.53637350705756
2014	66.18690029203171