Year	% of total
1990	0.0351253970467647
1995	0.0351416365854895
2000	0.177794617086424
2005	0.181172484534808
2010	0.185266269991002
2011	0.186573943942614
2012	0.186740677478547
2013	0.170335533363852
2014	0.120884702416346
2015	0.104533778950666
2016	0.0545427047125235
2017	0.0545981931093675