Year	% of total fuel combustion
1971	51.808278867102395
1972	48.38573538721249
1973	47.5281715739731
1974	44.48
1975	39.60749330954505
1976	36.7367535744323
1977	33.706770579639546
1978	37.51306165099268
1979	38.380927429918785
1980	40.49190161967607
1981	41.12636062470421
1982	40.489576013117826
1983	41.901284014607135
1984	41.24911785462244
1985	38.21663533834586
1986	39.696005655708724
1987	35.32213885911635
1988	36.777005536576745
1989	40.01965494649487
1990	38.958956819153485
1991	35.665547492689264
1992	38.781339257378605
1993	37.2729087642244
1994	37.547132367533244
1995	36.919015744319786
1996	37.78712958092232
1997	41.73261491833642
1998	41.95704855017966
1999	38.227222832052696
2000	41.52177655362368
2001	41.58624604654935
2002	39.87285027304589
2003	40.01307616868257
2004	37.60482796457402
2005	37.18369430467439
2006	41.1813269288502
2007	44.06936416184971
2008	41.53595181327645
2009	41.86089991275083
2010	35.14317373301453
2011	34.52742894910772
2012	34.891851851851854
2013	36.79148499615286
2014	35.54422865991354