Year	% of total fuel combustion
1960	2.648872014649908
1961	2.5888063543428688
1962	2.7157045035223826
1963	2.754962122240626
1964	2.6151610694047402
1965	2.7769353396321783
1966	2.7889571524003243
1967	2.6892368766130903
1968	2.810880600638233
1969	2.775673892336408
1970	2.0137184940519033
1971	2.7016456201222003
1972	2.636497015185071
1973	2.6630541108955446
1974	2.7181918110805023
1975	2.9524468093164984
1976	2.796352272145089
1977	2.695644671313741
1978	2.729336862422271
1979	2.8906474988130353
1980	2.7453133104204044
1981	2.7760667763317946
1982	2.6378271108576805
1983	2.773305983261063
1984	2.3434894331113316
1985	2.348249428131952
1986	2.3578168608975436
1987	2.3266490228013033
1988	2.130737775956887
1989	2.0627633787421504
1990	2.0133817763228894
1991	1.9942258388743543
1992	1.6813198297052565
1993	1.6541365685255933
1994	1.6034683284231868
1995	1.619423058172746
1996	1.5804163559163662
1997	1.5371759274862231
1998	1.4785590757144815
1999	1.4132133774226339
2000	1.4024798100001088
2001	1.395970756812296
2002	1.3911679930843672
2003	1.2758671145066278
2004	1.3626098358728331
2005	1.4633536740256359
2006	1.4624469117100423
2007	1.38574077470098
2008	1.3780268513201415
2009	1.3635407670588027
2010	1.383103375298739
2011	1.3261358917761215
2012	1.3339565559441333
2013	1.3604370671758943
2014	1.3353806652989817