Year	Percent
1986-01-01	74.4842796296304
1987-01-01	73.4813688074390
1988-01-01	69.9533499608749
1989-01-01	67.7086105926086
1990-01-01	68.4874319711880
1991-01-01	67.3931252745583
1992-01-01	65.5248467009503
1993-01-01	64.6931246177900
1994-01-01	66.0267252762209
1995-01-01	67.1020389728681
1996-01-01	66.9822334886748
1997-01-01	66.7212786503553
1998-01-01	64.9481724854272
1999-01-01	62.9422413084051
2000-01-01	62.6775015385599
2001-01-01	62.9651684964280
2002-01-01	63.6401669416732
2003-01-01	62.4099554265529
2004-01-01	62.1830114384980
2005-01-01	62.3487044905582
2006-01-01	64.4099564743045
2007-01-01	64.3727661351052
2008-01-01	62.6824581266579
2009-01-01	60.7055168370727
2010-01-01	59.0822808258531
2011-01-01	58.5469674174970
2012-01-01	58.3776009635800
2013-01-01	57.9210872156857
2014-01-01	60.0741275268856
2015-01-01	61.4914671170006
2016-01-01	62.5619491770150
2017-01-01	63.4255964454815