Quarter	Percent
1999-04-01	58.1
2000-01-01	56
2000-04-01	58.3
2000-07-01	57.7
2000-10-01	57.4
2001-01-01	56.3
2001-04-01	57.5
2001-07-01	60.3
2001-10-01	58.3
2002-01-01	56.4
2002-04-01	58.3
2002-07-01	58.7
2002-10-01	59.7
2003-01-01	59.3
2003-04-01	59.1
2003-07-01	60.4
2003-10-01	60.7
2004-01-01	61.2
2004-04-01	61.3
2004-07-01	60.6
2004-10-01	59.8
2005-01-01	62.6
2005-04-01	64.6
2005-07-01	62.1
2005-10-01	63.1
2006-01-01	65.1
2006-04-01	66.6
2006-07-01	65.1
2006-10-01	65.5
2007-01-01	65.6
2007-04-01	66.8
2007-07-01	67
2007-10-01	65.6
2008-01-01	65.3
2008-04-01	66.4
2008-07-01	67.7
2008-10-01	67
2009-01-01	64.7
2009-04-01	63.6
2009-07-01	62.1
2009-10-01	62.5
2010-01-01	61.3
2010-04-01	60.8
2010-07-01	60.1
2010-10-01	61
2011-01-01	60.7
2011-04-01	62.6
2011-07-01	64.8
2011-10-01	63.8
2012-01-01	64.3
2012-04-01	65.5
2012-07-01	64.9
2012-10-01	64.2
2013-01-01	65
2013-04-01	66.4
2013-07-01	65.4
2013-10-01	66
2014-01-01	64.4
2014-04-01	66.6
2014-07-01	67.4
2014-10-01	66.9
2015-01-01	67.1
2015-04-01	68.1
2015-07-01	69.9
2015-10-01	68.8
2016-01-01	67.6
2016-04-01	70.1
2016-07-01	68.4
2016-10-01	68.3
2017-01-01	70.2
2017-04-01	69.8
2017-07-01	71.1
2017-10-01	72.6
2018-01-01	71.0
2018-04-01	71.1