Year	% of total fuel combustion
1971	70.10435850214856
1972	68.05031446540879
1973	70.77885162023878
1974	69.95142262317835
1975	72.33038348082597
1976	67.96941376380629
1977	68.83830455259026
1978	69.25373134328358
1979	71.86177715091678
1980	8.99328859060403
1981	14.267015706806282
1982	14.598540145985398
1983	12.921669525443116
1984	8.347725964306274
1985	1.0900745840504884
1986	0.9419152276295131
1987	1.8535681186283606
1988	1.6746411483253583
1989	1.2485811577752555
1990	4.085155350978136
1991	4.098360655737704
1992	4.355203619909502
1993	5.116058739933678
1994	4.912430585219991
1995	3.897996357012751
1996	3.755260602136611
1997	3.2976092333058524
1998	2.984332255657796
1999	2.8805562453439277
2000	2.5554047942107654
2001	2.316048370567738
2002	2.256428196606611
2003	2.2719734660033186
2004	2.1241830065359486
2005	2.0862308762169675
2006	1.9776440240756663
2007	1.82648401826484
2008	1.6344725111441305
2009	1.4874551971326164
2010	1.3006582599730347
2011	1.2978740345568915
2012	1.2025012025012023
2013	1.115213044147054
2014	1.1443723396832042