Year	% of energy use
1971	61.93608488452143
1972	64.03029276476933
1973	64.34425974930937
1974	65.00121539483789
1975	64.65880325427743
1976	66.32226358220784
1977	66.44270984321231
1978	64.82383701502926
1979	64.99361279223262
1980	66.98349952556346
1981	66.22486124046458
1982	63.795705652269405
1983	64.8962017258565
1984	62.910392713045496
1985	62.995480851615845
1986	61.54919759767452
1987	62.77115380270336
1988	62.482207111499065
1989	61.60215712064735
1990	56.57485477248024
1991	54.697023498984535
1992	47.19087066243557
1993	50.44289996886637
1994	50.441923149250925
1995	54.4492440465553
1996	53.28618012283579
1997	55.703693916565896
1998	55.24658787942776
1999	48.58963111409625
2000	44.866925794004366
2001	41.357152746478604
2002	36.27301981077439
2003	37.45055369805127
2004	40.48814761987226
2005	46.80395365533169
2006	47.74708684248025
2007	45.74323570096783
2008	49.4776063956253
2009	53.97094997832428
2010	57.465748951982995
2011	53.317548224959424
2012	53.965122561002
2013	53.571207771675645
2014	49.77823923801278