Year	% of total fuel combustion
1971	9.657320872274143
1972	5.865102639296188
1973	5.286343612334801
1974	2.3419203747072603
1975	3.4267912772585674
1976	3.1347962382445145
1977	3.2448377581120944
1978	2.5974025974025974
1979	1.910828025477707
1980	3.2697547683923704
1981	3.6312849162011176
1982	3.532608695652174
1983	4
1984	3.903903903903904
1985	3.015075376884422
1986	3.571428571428572
1987	4
1988	2.9680365296803655
1989	3.2911392405063293
1990	2.6465028355387528
1991	3.382663847780126
1992	3.611738148984199
1993	4.854368932038835
1994	3.9215686274509802
1995	4.408352668213458
1996	6.585365853658538
1997	5.5226824457593695
1998	6.277056277056277
1999	6.679764243614931
2000	2.3722627737226274
2001	3.322259136212625
2002	4.155495978552279
2003	4.712041884816754
2004	4.410011918951132
2005	4.86815415821501
2006	4.6303818034118605
2007	4.60377358490566
2008	4.184100418410042
2009	4.709897610921502
2010	5.076820307281229
2011	7.631954350927248
2012	7.9120879120879115
2013	6.72579453067258
2014	6.521739130434784