Year	Percent
1986-01-01	63.1435395092011
1987-01-01	63.6403485111164
1988-01-01	62.9039796101017
1989-01-01	61.6728794610633
1990-01-01	62.9843317195635
1991-01-01	63.4481864870513
1992-01-01	63.3031535663992
1993-01-01	63.3097116552593
1994-01-01	64.5602650196091
1995-01-01	65.5909108704848
1996-01-01	67.0909521555885
1997-01-01	66.9312662720829
1998-01-01	66.7465614667086
1999-01-01	67.0531367935756
2000-01-01	67.1777597289918
2001-01-01	68.1517046869855
2002-01-01	68.8033313460460
2003-01-01	68.9724744397187
2004-01-01	69.2035883720772
2005-01-01	70.3771333361223
2006-01-01	70.9761987409044
2007-01-01	71.4331705497271
2008-01-01	71.5948058923606
2009-01-01	71.5180873480431
2010-01-01	71.2314949219178
2011-01-01	71.6426445074073
2012-01-01	71.8068746008112
2013-01-01	72.5248491116156
2014-01-01	73.7091651820665
2015-01-01	73.6770477300290
2016-01-01	74.9192081750972
2017-01-01	76.1603676510434