Year	Percent
1991-01-01	70.3929977416992
1992-01-01	70.3789978027344
1993-01-01	70.4840011596680
1994-01-01	66.0999984741211
1995-01-01	63.7309989929199
1996-01-01	62.2130012512207
1997-01-01	62.0800018310547
1998-01-01	62.0159988403320
1999-01-01	61.6809997558594
2000-01-01	61.9589996337891
2001-01-01	63.2099990844727
2002-01-01	63.6769981384277
2003-01-01	63.6949996948242
2004-01-01	63.4129981994629
2005-01-01	63.8489990234375
2006-01-01	64.2710037231445
2007-01-01	64.8960037231445
2008-01-01	65.6520004272461
2009-01-01	65.4270019531250
2010-01-01	66.2720031738281
2011-01-01	66.5670013427734
2012-01-01	66.7399978637695
2013-01-01	66.9410018920898
2014-01-01	67.3020019531250
2015-01-01	67.4209976196289
2016-01-01	67.4810028076172
2017-01-01	67.5240020751953