Year	% of total fuel combustion
1960	10.038314176245212
1961	10.224800580130529
1962	10.79136690647482
1963	10.831586303284418
1964	11.216216216216216
1965	12.11484593837535
1966	11.783439490445861
1967	11.962286387743076
1968	11.48684916800859
1969	12.641898864809084
1970	13.39468302658487
1971	13.077634011090572
1972	14.118747078073865
1973	15.994236311239193
1974	15.183709606020363
1975	16.225165562913908
1976	16.095107453132144
1977	16.737649063032368
1978	19.95689655172414
1979	17.49260355029586
1980	17.57435303205871
1981	17.75009731413001
1982	17.174515235457065
1983	16.520700636942674
1984	16.184738955823295
1985	16.86200378071834
1986	16.05972323379461
1987	14.604810996563572
1988	15.516014234875444
1989	15.908313376667808
1990	16.273663234805714
1991	16.569010416666664
1992	17.839766461239055
1993	17.844465956760246
1994	18.008739076154807
1995	18.081520073551946
1996	20.364920541495
1997	20.834524149757073
1998	23.00531914893617
1999	24.501278772378516
2000	25.30002449179525
2001	25.116387337057727
2002	26.116920152091254
2003	26.61424827257565
2004	27.890514393581878
2005	28.594032549728755
2006	30.347268303472685
2007	32.26096737907761
2008	30.65395095367848
2009	30.851063829787233
2010	29.341469616069162
2011	30.124929017603634
2012	28.943681703558422
2013	30.340017436791634
2014	32.132309509746015