Year	% of total
1990	92.5879971057955
1995	92.5886592798134
2000	91.6353812876017
2005	91.6393068918169
2010	91.6359385521946
2011	91.6311392912133
2012	91.6256275913778
2013	91.6200937213305
2014	91.6120903603093
2015	91.614182431085
2016	91.5880397222927
2017	91.6115461192844