Year	Percent
1991-01-01	63.6910018920898
1992-01-01	63.7859992980957
1993-01-01	64.0149993896484
1994-01-01	64.3369979858398
1995-01-01	64.6880035400391
1996-01-01	64.4160003662109
1997-01-01	64.2060012817383
1998-01-01	64.1979980468750
1999-01-01	64.4449996948242
2000-01-01	64.9240036010742
2001-01-01	64.9639968872070
2002-01-01	65.2360000610352
2003-01-01	65.8740005493164
2004-01-01	66.7539978027344
2005-01-01	67.7389984130859
2006-01-01	68.1669998168945
2007-01-01	68.8539962768555
2008-01-01	69.7009963989258
2009-01-01	70.5859985351563
2010-01-01	71.4039993286133
2011-01-01	70.5390014648438
2012-01-01	70.6380004882813
2013-01-01	70.6559982299805
2014-01-01	70.7060012817383
2015-01-01	70.7750015258789
2016-01-01	70.9919967651367
2017-01-01	71.3300018310547