Year	% of total
1990	63.1855879009278
1995	64.6522930022596
2000	66.2084864717358
2005	76.2473104632472
2010	76.6159707587517
2011	71.9712285464736
2012	70.2457644378534
2013	70.000241113451
2014	63.9839573831623
2015	57.5214109458516
2016	54.5218421364749
2017	54.6902789971692