Year	% of total fuel combustion
1971	20.610687022900763
1972	17.355371900826448
1973	22.307692307692307
1974	21.21212121212121
1975	18.64406779661017
1976	20.33898305084746
1977	20.51282051282051
1978	18.4
1979	15.909090909090908
1980	18.51851851851852
1981	24.832214765100673
1982	15.555555555555554
1983	14.482758620689657
1984	15.555555555555554
1985	16.54676258992806
1986	19.51219512195122
1987	17.204301075268816
1988	21.243523316062177
1989	24.137931034482758
1990	25.34562211981567
1991	25.33936651583711
1992	18.705035971223026
1993	21.666666666666668
1994	24.637681159420293
1995	24.13793103448276
1996	23.552123552123554
1997	24.000000000000004
1998	24.65753424657534
1999	24.315068493150687
2000	24.6875
2001	23.762376237623762
2002	23.752969121140143
2003	20.787746170678332
2004	23.125000000000004
2005	25.612472160356344
2006	25.625000000000004
2007	24.675324675324678
2008	23.509369676320272
2009	22.537562604340568
2010	28.859060402684563
2011	35.662299854439595
2012	31.499312242090788
2013	33.76470588235294
2014	34.17305585980285