Year	% of total fuel combustion
1960	19.7376267143709
1961	19.68312004875076
1962	21.64058283864004
1963	16.21488417939872
1964	21.672661870503596
1965	22.81964436917866
1966	24.844036697247702
1967	22.718052738336713
1968	23.26748196926936
1969	26.795895096921324
1970	26.2936695560809
1971	23.061966884094332
1972	23.522223819543367
1973	24.13661632311704
1974	24.056822092733466
1975	24.056407908605987
1976	24.13232979539126
1977	24.3441204504863
1978	25.47460804362645
1979	26.63242056423216
1980	28.780087842904585
1981	28.793841522841387
1982	28.966442095852358
1983	29.17059945387666
1984	29.361321855850598
1985	31.05581132902771
1986	32.21118456807534
1987	32.49646679107012
1988	33.06342862935306
1989	34.86579604788009
1990	44.79461596506956
1991	45.88671219182428
1992	47.36211186354033
1993	47.26064376799671
1994	48.2185582447631
1995	46.69967766825967
1996	49.363113461360065
1997	48.92341414094638
1998	49.617535622279675
1999	50.49533080272933
2000	51.45642697014687
2001	51.970285119708876
2002	52.63751739700765
2003	53.44905692757895
2004	51.14667204434752
2005	51.03682807372197
2006	51.948362702968865
2007	51.36816762453084
2008	50.5944367648492
2009	50.71305684136183
2010	51.69989332429496
2011	52.13368212049602
2012	52.38247895257213
2013	52.66225028916181
2014	52.10578564389222