Year	Percent
1991-01-01	63.1889991760254
1992-01-01	62.8810005187988
1993-01-01	62.6319999694824
1994-01-01	62.3530006408691
1995-01-01	62.0900001525879
1996-01-01	62.3429985046387
1997-01-01	62.6559982299805
1998-01-01	63.0559997558594
1999-01-01	63.5810012817383
2000-01-01	64.0390014648438
2001-01-01	65.1009979248047
2002-01-01	66.3610000610352
2003-01-01	67.6029968261719
2004-01-01	68.1579971313477
2005-01-01	68.5400009155273
2006-01-01	68.9540023803711
2007-01-01	68.8349990844727
2008-01-01	68.9319992065430
2009-01-01	68.8639984130859
2010-01-01	67.5080032348633
2011-01-01	65.7799987792969
2012-01-01	64.2160034179688
2013-01-01	64.2009963989258
2014-01-01	62.6920013427734
2015-01-01	64.9739990234375
2016-01-01	64.9049987792969
2017-01-01	65.1610031127930