Year	% of total electricity output
1990	23.872313807667545
1991	23.903226610309797
1992	24.135013050150974
1993	25.197311192311577
1994	25.979550653050495
1995	25.974571656282336
1996	25.165993277745166
1997	24.8211517388811
1998	25.13107533768161
1999	24.385330800224697
2000	23.65998323058086
2001	23.332206791743044
2002	22.66019947703045
2003	21.617651979170166
2004	22.181443308325093
2005	22.166075682134533
2006	21.78894537438528
2007	21.09357330683584
2008	21.491992632964408
2009	21.724793229518898
2010	22.03740212114654
2011	21.20771391984885
2012	22.214589831531022
2013	22.51191835962058
2014	23.04745660713028
2015	23.518269223204793