Year	% of total electricity output
1990	17.517699483726037
1991	17.156023824479124
1992	17.032222089956207
1993	17.68880871368221
1994	16.770368531863138
1995	17.319894154327045
1996	17.30392554859867
1997	17.089639822652444
1998	16.314002994896477
1999	16.092984032157887
2000	15.856760041982842
2001	15.060697676093211
2002	15.377596079866679
2003	15.17392978879083
2004	15.47174695776891
2005	15.506664423346951
2006	15.919531012861897
2007	15.76979366829908
2008	16.717227687221524
2009	17.74030278598399
2010	18.060207961811024
2011	19.47831413213018
2012	20.459787843268106
2013	21.685329347757104
2014	22.510847220129044
2015	23.335963455377225