Quarter	Percent
1999-01-01	54.5
1999-04-01	55.4
1999-07-01	54.7
1999-10-01	55.5
2000-01-01	56.9
2000-04-01	57.2
2000-07-01	56.4
2000-10-01	56.9
2001-01-01	58.8
2001-04-01	61.1
2001-07-01	61.1
2001-10-01	62.1
2002-01-01	63.6
2002-04-01	63.9
2002-07-01	63.6
2002-10-01	65
2003-01-01	64.7
2003-04-01	65.5
2003-07-01	64.9
2003-10-01	66.7
2004-01-01	67.9
2004-04-01	69.2
2004-07-01	68.5
2004-10-01	68.7
2005-01-01	69.3
2005-04-01	70.1
2005-07-01	69.6
2005-10-01	69.7
2006-01-01	71
2006-04-01	70.7
2006-07-01	68.8
2006-10-01	68.6
2007-01-01	70.1
2007-04-01	70.7
2007-07-01	70.2
2007-10-01	70.8
2008-01-01	71.6
2008-04-01	71.7
2008-07-01	69.9
2008-10-01	72
2009-01-01	73.2
2009-04-01	72.5
2009-07-01	71.4
2009-10-01	71.9
2010-01-01	72.7
2010-04-01	72.8
2010-07-01	72.1
2010-10-01	72.2
2011-01-01	72.9
2011-04-01	73.4
2011-07-01	72
2011-10-01	73.6
2012-01-01	74.5
2012-04-01	73.4
2012-07-01	70.8
2012-10-01	69.7
2013-01-01	71
2013-04-01	70.5
2013-07-01	67.1
2013-10-01	67.5
2014-01-01	67.3
2014-04-01	67.5
2014-07-01	66.3
2014-10-01	66.8
2015-01-01	67.1
2015-04-01	65.9
2015-07-01	64.5
2015-10-01	64.9
2016-01-01	64.9
2016-04-01	63.9
2016-07-01	63.1
2016-10-01	63.5
2017-01-01	64.9
2017-04-01	63.4
2017-07-01	62.7
2017-10-01	63.1
2018-01-01	64.1
2018-04-01	63.4