Year	% of energy use
1971	8.400492961865917
1972	7.683795537546298
1973	7.691867290611014
1974	8.201053247654531
1975	8.09230550270241
1976	10.685680893772123
1977	10.63679404043351
1978	11.092942601630343
1979	10.896807998268706
1980	9.896349923426632
1981	9.517007116575734
1982	11.652034982529326
1983	12.954622735502117
1984	13.378462830284569
1985	13.256040351910151
1986	16.492506883176226
1987	17.64753806809037
1988	18.53231601293715
1989	19.491306633768044
1990	19.734221440692295
1991	18.64182732413237
1992	16.760314032274522
1993	14.372123628118082
1994	4.393400396811595
1995	17.76939259318757
1996	17.86149782310503
1997	22.452634781092883
1998	20.656777386786583
1999	22.03207181127295
2000	23.30767711668762
2001	24.888909445435754
2002	24.962735592900316
2003	24.55436446890741
2004	27.713821001747135
2005	19.49572622974018
2006	19.38001493520805
2007	20.995340675991127
2008	20.72859994572913
2009	19.293159885168272
2010	17.774608838023134
2011	17.960165368201757
2012	18.04963097841368
2013	18.69779908191781
2014	22.015869961956504