Year	% of total
1990	72.2749290328885
1995	72.2113662016143
2000	68.4514341238652
2005	68.7467913287423
2010	69.0110268683452
2011	69.0598081418208
2012	69.107475088136
2013	69.1539327723892
2014	59.1070663058089
2015	59.0910860354427
2016	55.1177731256537
2017	59.0516829607446