Year	% of total fuel combustion
1960	19.96604075109868
1961	20.13877695754489
1962	21.818806893768404
1963	23.93111142100126
1964	21.741644034526338
1965	21.7442596156381
1966	22.029388247322686
1967	22.256664205514674
1968	22.528998724413768
1969	22.76913042516969
1970	23.743061645187797
1971	22.96057952822725
1972	23.303563480995763
1973	23.12606864007206
1974	21.236451061375835
1975	21.986300199859926
1976	21.36682841915754
1977	21.089373018639986
1978	21.577550988464004
1979	21.14602212479225
1980	19.960100635920234
1981	19.49927372498386
1982	19.103379896331436
1983	18.92068060611191
1984	20.958848843464228
1985	21.846632480639325
1986	22.212232087480277
1987	21.575253444242268
1988	20.383150929619536
1989	18.735302331793918
1990	18.962656090011414
1991	19.79185735373734
1992	19.026875547026183
1993	19.509349142466434
1994	18.341003617749124
1995	18.373406720741595
1996	19.784860902122706
1997	18.705845402753532
1998	18.37321922822457
1999	18.15281474908804
2000	17.397093956840173
2001	18.29136531592324
2002	17.299531107308127
2003	17.779163364421386
2004	17.612643785654164
2005	17.6605814739689
2006	17.50484071037425
2007	15.296691486911799
2008	17.186303168623283
2009	18.008268995485807
2010	18.302390531379565
2011	16.61207901776528
2012	17.305688232739904
2013	18.167279281826534
2014	16.403138032277973