Year	% of total fuel combustion
1971	18.558951965065503
1972	20.883534136546185
1973	30.046948356807512
1974	26.964560862865948
1975	26.26970227670753
1976	29.9047619047619
1977	38.82863340563991
1978	32.068965517241374
1979	29.20634920634921
1980	47.51879699248121
1981	46.129541864139014
1982	57.05128205128205
1983	47.20616570327553
1984	43.48623853211009
1985	44.93192133131619
1986	48.1586402266289
1987	45.78146611341632
1988	52.83363802559414
1989	50.81669691470054
1990	50.81669691470054
1991	45.611510791366904
1992	37.971014492753625
1993	31.584158415841586
1994	31.859205776173283
1995	28.303362001563727
1996	37.34034560480841
1997	38.93630991464215
1998	53.597848016139885
1999	51.75718849840255
2000	51.39385275196568
2001	50.231023102310225
2002	56.35761589403974
2003	56.74418604651162
2004	49.045424621461486
2005	50.829875518672196
2006	60.2489019033675
2007	67.02747710241465
2008	61.00190234622702
2009	51.73845355474831
2010	61.81318681318682
2011	63.1891891891892
2012	57.42857142857143
2013	62.6937984496124
2014	57.21949038891373