Year	% of total fuel combustion
1971	5.08504143044047
1972	8.392494929006086
1973	8.505693702068324
1974	9.277953301995838
1975	8.188091342391692
1976	3.6095908261662757
1977	3.316532885321386
1978	2.9998852816335897
1979	2.8032676812891673
1980	2.723581820232322
1981	2.887844190732035
1982	2.5559648625672997
1983	2.2887520984890877
1984	2.338479130931961
1985	5.163835992451535
1986	5.155555555555555
1987	4.966378990840261
1988	4.75772743691625
1989	4.450647845781101
1990	5.186857584219595
1991	6.337271750805584
1992	5.690072639225182
1993	5.372224640835873
1994	4.788180847276611
1995	5.1691889134500935
1996	4.9880056249483005
1997	6.692022095445077
1998	8.198590381426202
1999	8.579703149511282
2000	8.62708719851577
2001	7.957530647985989
2002	8.095028596568412
2003	9.154639175257731
2004	10.1429180887372
2005	10.554716166630692
2006	12.022660511959717
2007	10.445501730103805
2008	9.063013698630137
2009	10.688008261262425
2010	11.00856072766185
2011	10.197775030902347
2012	10.965526014501972
2013	12.231884057971014
2014	11.737089201877934