Year	% of total fuel combustion
1960	20.095408467501493
1961	19.19561243144424
1962	18.29465731246627
1963	20.25628388368655
1964	17.26618705035971
1965	16.596104995766296
1966	16.440366972477065
1967	17.849898580121703
1968	17.24678582627783
1969	17.50285062713797
1970	18.360914105594958
1971	18.559809924152425
1972	19.94471435751382
1973	18.7042842215256
1974	18.400936037441497
1975	18.31160317575934
1976	18.886198547215496
1977	17.833355099908584
1978	19.964485032978182
1979	19.601328903654483
1980	21.24365016218863
1981	21.58673921295711
1982	21.410972898263324
1983	21.5007299270073
1984	22.688690066529023
1985	22.372128305158213
1986	19.328165374677
1987	20.452109519633638
1988	24.790316910250613
1989	24.29937669505638
1990	16.708756081157116
1991	16.262825710414383
1992	16.446601367147043
1993	14.762056601440742
1994	13.351052277019242
1995	15.95465371058398
1996	15.019337865194208
1997	15.159615376620787
1998	14.693410794477552
1999	14.31154503050474
2000	14.989752341447085
2001	14.688507091980213
2002	14.904810536552016
2003	14.872362737118886
2004	15.217800948462672
2005	14.418054403747972
2006	13.838845803777618
2007	14.862063113780406
2008	14.44254281382634
2009	13.756187996765474
2010	14.245233357351658
2011	14.519019059702494
2012	13.946098496272997
2013	14.237778969213544
2014	13.730547414200624