Year	% of total fuel combustion
1971	62.54125412541255
1972	69.94459833795015
1973	70.19704433497537
1974	70.44917257683214
1975	68.36492890995261
1976	67.76315789473685
1977	66.60117878192536
1978	68.51063829787235
1979	67.24546172059985
1980	68.45849802371542
1981	68.73614190687363
1982	69.07142857142857
1983	70.21839841164791
1984	69.53473550031867
1985	65.72289156626505
1986	67.41973840665874
1987	68.25304701102728
1988	73.19796954314722
1989	71.63187855787476
1990	79.90331491712706
1991	78.36506894287591
1992	81.08280254777071
1993	83.51313969571233
1994	83.06111696522656
1995	82.06015437849348
1996	84.03012204622176
1997	83.54297693920337
1998	83.69330453563715
1999	83.91534391534393
2000	78.37132003798672
2001	77.64034253092294
2002	76.58595641646491
2003	73.04165575058947
2004	72.64008076728925
2005	70.15319598520867
2006	69.43573667711598
2007	68.77219685438864
2008	67.80177890724269
2009	60.15373171336474
2010	60.11743450767841
2011	59.97004706889173
2012	59.856396866840726
2013	58.32612456747405
2014	58.649602824360116