Year	% of energy use
1990	92.65877712603795
1991	92.16098652323137
1992	90.53596654911767
1993	89.7734863433474
1994	87.12375378329304
1995	86.58923820763353
1996	86.91079820556656
1997	86.9151147243215
1998	87.13570980327376
1999	85.49897705433833
2000	86.16671052077932
2001	85.83853954454675
2002	85.77695139890852
2003	86.59862840050884
2004	86.83924100533785
2005	86.18004133097457
2006	86.76438607510718
2007	86.19836237558773
2008	86.31206617624002
2009	85.63561114382635
2010	85.6224329737371
2011	85.89553715340257
2012	86.50142767654721
2013	85.38962705406958
2014	86.77969892703159