Quarter	Percent
1999-04-01	69.2
1999-07-01	71.9
1999-10-01	70.7
2000-01-01	70.6
2000-04-01	71.1
2000-07-01	73.2
2000-10-01	71.6
2001-01-01	71.4
2001-04-01	71.6
2001-07-01	73.4
2001-10-01	71.6
2002-01-01	70.6
2002-04-01	70.5
2002-07-01	71.9
2002-10-01	70.6
2003-01-01	70.1
2003-04-01	70.2
2003-07-01	71.4
2003-10-01	70.8
2004-01-01	70.9
2004-04-01	70.5
2004-07-01	72.3
2004-10-01	71.3
2005-01-01	71.3
2005-04-01	71.6
2005-07-01	73.4
2005-10-01	72.3
2006-01-01	72.6
2006-04-01	72.8
2006-07-01	74.1
2006-10-01	73.3
2007-01-01	75.7
2007-04-01	75.8
2007-07-01	76.6
2007-10-01	75.1
2008-01-01	73.9
2008-04-01	73.5
2008-07-01	72.9
2008-10-01	70.1
2009-01-01	66.0
2009-04-01	64.6
2009-07-01	63.8
2009-10-01	62.4
2010-01-01	61.1
2010-04-01	61.4
2010-07-01	61.4
2010-10-01	60.0
2011-01-01	59.4
2011-04-01	60.0
2011-07-01	59.9
2011-10-01	59.8
2012-01-01	58.8
2012-04-01	59.3
2012-07-01	60.0
2012-10-01	60.0
2013-01-01	60.2
2013-04-01	61.2
2013-07-01	62.6
2013-10-01	63.1
2014-01-01	62.3
2014-04-01	62.8
2014-07-01	64.1
2014-10-01	64.4
2015-01-01	64.1
2015-04-01	65.2
2015-07-01	65.9
2015-10-01	65.3
2016-01-01	65.0
2016-04-01	66.3
2016-07-01	67.4
2016-10-01	67.2
2017-01-01	66.7
2017-04-01	67.1
2017-07-01	68.1
2017-10-01	68.2
2018-01-01	68.1
2018-04-01	68.2