Year	% of total fuel combustion
1971	35.136180321529196
1972	35.422864428389296
1973	34.66468116789874
1974	34.68875995673124
1975	35.55934232948003
1976	35.49638055842813
1977	35.81155375116299
1978	35.96181509088531
1979	33.17537448295249
1980	31.020532783756966
1981	30.091628488129945
1982	33.062233644555775
1983	31.252285191956126
1984	31.36125945705385
1985	30.28658098507224
1986	32.36526654322191
1987	30.437436419125124
1988	29.397781299524567
1989	29.339444056989137
1990	27.902943006353574
1991	26.5769466049113
1992	26.020245429669792
1993	24.56476267095736
1994	24.735230026057938
1995	21.994404250508705
1996	20.97331748946743
1997	21.744753319589737
1998	22.39155624968512
1999	21.504987036042138
2000	21.049144243295448
2001	20.80820132122578
2002	21.614861687117877
2003	19.86979221269369
2004	19.663123498691977
2005	21.435187758202265
2006	22.3964126807564
2007	22.92256360790019
2008	23.47209525295993
2009	24.28175827952441
2010	25.9738060291295
2011	26.863977441093535
2012	25.184837722531217
2013	26.96954320201246
2014	26.40827461912095