Year	% of total fuel combustion
1971	11.783501161890008
1972	11.527127751776739
1973	10.7188093730209
1974	10.664348330073173
1975	10.701858052655767
1976	10.507605338306428
1977	9.337010930636428
1978	8.561107242339833
1979	7.64032154798321
1980	7.169382806985238
1981	6.6450928973944094
1982	6.111787380807465
1983	6.130420545446039
1984	6.792653836355638
1985	6.2983720309581
1986	6.5308353834184905
1987	6.605174086023634
1988	6.305954901742264
1989	6.740224203371878
1990	6.441646158544252
1991	6.432327306778075
1992	6.10497011381315
1993	6.352577131935807
1994	6.449163227877122
1995	6.311393859563078
1996	6.761110137621481
1997	6.766176790350844
1998	6.2726345320071415
1999	6.274979512072119
2000	6.35902450950431
2001	6.126111708086605
2002	5.985459178070157
2003	5.756287258819257
2004	6.11172845741994
2005	6.199341795956745
2006	5.688660311088811
2007	5.650951426925424
2008	5.48389662027833
2009	5.299802477731445
2010	4.836121934448774
2011	4.814050017729386
2012	4.769159349030018
2013	4.709344152856004
2014	4.44788711363297