Year	% of energy use
1991	55.05493904300103
1992	58.89988082177512
1993	63.023154116999535
1994	67.90502210266223
1995	65.76715768222485
1996	69.83688191408277
1997	71.83068547077333
1998	69.29553199140986
1999	67.1783997896374
2000	63.02361546827392
2001	69.75999589750717
2002	65.3793543395306
2003	66.54407478276376
2004	68.21300728186695
2005	68.54756703258239
2006	69.25539316975609
2007	69.63890579998595
2008	72.04105595622605
2009	72.07448406000351
2010	73.60844523512539
2011	73.19643382165457
2012	72.64562929840336
2013	75.30615264766118
2014	74.44166879409099