Year	% of total fuel combustion
1960	10.03861003861004
1961	9.746954076850985
1962	5.870646766169154
1963	9.668508287292818
1964	8.87728459530026
1965	6.530958439355386
1966	6.808859721082855
1967	6.239600665557404
1968	5.906480721903199
1969	10.990712074303405
1970	11.99421965317919
1971	10.888888888888888
1972	13.380736910148675
1973	19.221556886227546
1974	19.838987924094305
1975	14.850882531953744
1976	21.61716171617162
1977	23.87820512820513
1978	22.515101592531572
1979	15.464547677261614
1980	12.9933211900425
1981	15.13846153846154
1982	21.794871794871796
1983	23.80952380952381
1984	22.993492407809104
1985	25.132275132275133
1986	20.469798657718123
1987	23.20961840041819
1988	21.41107300342969
1989	20.944958597174864
1990	20.791168353265867
1991	22.348141432456934
1992	25.588235294117645
1993	22.801024765157983
1994	19.64586846543002
1995	18.13623067279565
1996	21.130713712910985
1997	27.262693156732894
1998	26.0202171471359
1999	28.850942725008892
2000	27.26958923023818
2001	30.734680782803974
2002	27.7992277992278
2003	30.876554443433424
2004	30.342275670675306
2005	34.98516320474778
2006	34.774881516587676
2007	31.248083409996934
2008	33.00448430493274
2009	29.382797110965196
2010	27.973640856672148
2011	27.015177065767286
2012	29.86222364626722
2013	26.679586563307495
2014	23.719590268886044