Year	% of total
1990	67.0921939642446
1995	63.7561848924894
2000	77.5561785959323
2005	78.1175656119811
2010	75.2499936023768
2011	78.1304290744464
2012	73.6740688238941
2013	71.070624588002
2014	67.8034221833599
2015	69.5309345723717
2016	62.932581473463
2017	63.1747795055999