Year	% of energy use
1971	41.384790645299866
1972	41.057499644349505
1973	43.47669164462475
1974	44.061609718039875
1975	43.40021363124911
1976	44.58570280921265
1977	49.685107302625184
1978	47.04844620158488
1979	37.35798922192698
1980	40.836639498448946
1981	41.19662305809028
1982	40.009738336481234
1983	40.66188296939905
1984	34.35810984503067
1985	33.14614188166242
1986	37.94207923252809
1987	37.84430806203235
1988	36.37733737831971
1989	30.66319518536759
1990	29.622683000032684
1991	28.918889780327945
1992	32.497590859030836
1993	32.68808445622561
1994	35.16180179064351
1995	37.33433019622529
1996	37.78773059414517
1997	39.48537601738282
1998	43.88295422866052
1999	47.03646036493752
2000	46.407582509018006
2001	48.36663330170161
2002	46.71916998090512
2003	48.08149086738999
2004	47.54165314157416
2005	47.93663474569815
2006	48.217818429140294
2007	49.363530307436164
2008	46.60205935796487
2009	47.33213902756308
2010	46.806605485718066
2011	48.511423850045745
2012	43.329659153105
2013	39.748991664502334
2014	40.85937540528269