Year	% of total fuel combustion
1971	14.25800193986421
1972	13.838120104438643
1973	16.1864406779661
1974	15.99063962558502
1975	17.965228589826143
1976	18.775933609958507
1977	17.00545364402578
1978	16.55658300308234
1979	17.49622926093514
1980	15.630956919557756
1981	16.356435643564357
1982	18.262150220913107
1983	14.467813894200129
1984	14.446417998815866
1985	15.200210748155952
1986	13.30977620730271
1987	13.590909090909092
1988	15.412695193672683
1989	15.264511388684793
1990	14.86924985684291
1991	15.886557528245332
1992	13.074258171411357
1993	10.92896174863388
1994	10.475708502024291
1995	10.67899936935043
1996	10.568438333675354
1997	8.582187582100008
1998	12.32634503662541
1999	16.554442437181805
2000	14.841089670828605
2001	13.518564664839271
2002	13.07415790174411
2003	10.119304297829524
2004	10.225089212187758
2005	9.56937799043062
2006	9.773781902552207
2007	13.04208673387742
2008	9.353412544901907
2009	7.788534754704666
2010	7.38092937880398
2011	9.058101768314687
2012	12.21984636097252
2013	10.46090108751942
2014	7.899028575480395