Year	% of total fuel combustion
1971	21.20593404321307
1972	21.859706362153343
1973	23.34982169561716
1974	24.53135798203179
1975	24.308335823125187
1976	25.019152076832523
1977	25.18770016976146
1978	23.80992960987167
1979	24.716283152548748
1980	26.601932991627713
1981	27.368923318738076
1982	28.618580466017896
1983	29.83057439412723
1984	29.92142337914085
1985	31.85849300880373
1986	33.717952673310094
1987	35.55182824555518
1988	35.78451585708919
1989	35.681497938260186
1990	41.69310321410208
1991	41.13761624273188
1992	40.96789857546021
1993	42.87724200833491
1994	42.084032134248005
1995	42.505537434929295
1996	41.924571724332345
1997	41.65983960463561
1998	42.63999685963894
1999	42.76321473977856
2000	43.31549504289684
2001	43.418255704907786
2002	43.41473935944784
2003	43.75776374955505
2004	43.83678901021974
2005	44.30344256713907
2006	44.10479794772801
2007	43.97404882340004
2008	43.98956915053193
2009	43.99274296631252
2010	43.963887475313705
2011	44.60700066063072
2012	45.77843098735699
2013	45.581511406844115
2014	46.4674760188485