Quarter	Percent
1999-04-01	65.9
2000-01-01	62.8
2000-04-01	63.6
2000-07-01	64.3
2000-10-01	62.8
2001-01-01	63.8
2001-04-01	63.7
2001-07-01	64
2001-10-01	65.3
2002-01-01	65
2002-04-01	64.7
2002-07-01	65.6
2002-10-01	63.2
2003-01-01	63.4
2003-04-01	65.9
2003-07-01	68.1
2003-10-01	67.6
2004-01-01	64.8
2004-04-01	65.1
2004-07-01	66.1
2004-10-01	66.7
2005-01-01	64.5
2005-04-01	65.7
2005-07-01	68.3
2005-10-01	68.4
2006-01-01	70.2
2006-04-01	71.7
2006-07-01	71.8
2006-10-01	71.9
2007-01-01	72.4
2007-04-01	73.5
2007-07-01	74.3
2007-10-01	73.7
2008-01-01	74.6
2008-04-01	73.8
2008-07-01	73.6
2008-10-01	72.9
2009-01-01	66.4
2009-04-01	64.5
2009-07-01	65.4
2009-10-01	61.1
2010-01-01	56.8
2010-04-01	58.7
2010-07-01	64.6
2010-10-01	66.7
2011-01-01	66.1
2011-04-01	66.5
2011-07-01	70.1
2011-10-01	68.4
2012-01-01	67.7
2012-04-01	68.8
2012-07-01	71.7
2012-10-01	70.5
2013-01-01	70
2013-04-01	72.4
2013-07-01	72.3
2013-10-01	70.7
2014-01-01	70.8
2014-04-01	73.5
2014-07-01	73.3
2014-10-01	74.2
2015-01-01	72.7
2015-04-01	75.3
2015-07-01	78.3
2015-10-01	75.0
2016-01-01	73.2
2016-04-01	76.6
2016-07-01	78.0
2016-10-01	74.9
2017-01-01	76.1
2017-04-01	76.7
2017-07-01	78.5
2017-10-01	78.3
2018-01-01	76.1
2018-04-01	78.5