Year	% of total fuel combustion
1971	18.511522478277293
1972	20.419325432999088
1973	20.72402169133812
1974	22.203602848764138
1975	26.582604220277915
1976	26.878110892464402
1977	26.50846770104452
1978	26.983240223463685
1979	27.377711787511338
1980	28.175519630484985
1981	30.363940916704735
1982	32.268638511968284
1983	32.28148361127084
1984	33.216644649933954
1985	31.6141049521485
1986	29.163838321505708
1987	27.064274682190803
1988	30.147978324301793
1989	30.47009598818607
1990	27.983254930732382
1991	29.84123259815423
1992	31.933717683744874
1993	32.14757563746862
1994	33.23148374480567
1995	33.723469787758305
1996	34.85976408912189
1997	37.72411906597369
1998	39.09702209414026
1999	37.64120743935025
2000	42.59340761159112
2001	44.63965176808472
2002	43.86661464668487
2003	44.77171975686669
2004	48.73267628309728
2005	49.948635002513605
2006	50.92670326122054
2007	53.244630696699836
2008	54.83547515756732
2009	57.4980574980575
2010	58.61111111111113
2011	60.410419136620405
2012	60.95746345194431
2013	60.43902268516901
2014	60.48502139800286