Year	% of total energy use
1990	24.39529754947307
1991	27.112603517367805
1992	23.972351316569824
1993	22.497388971569425
1994	25.06598347310158
1995	23.859835257368747
1996	22.781612656811156
1997	22.919062091687188
1998	23.759663481208136
1999	22.950324603623393
2000	23.34049011632376
2001	24.03917356976847
2002	24.467662873595902
2003	22.880674224144286
2004	24.055585518722765
2005	24.51621147220303
2006	23.47990079785313
2007	23.712329299300503
2008	24.655217359067187
2009	25.203725317273467
2010	24.656584216070126
2011	26.19567307515084
2012	25.311582563092767
2013	25.909776493609517
2014	31.862637302200763
2015	28.225847736256167