Quarter	Percent
1998-01-01	71
1998-04-01	71.9
1998-07-01	72.4
1998-10-01	71.7
1999-01-01	71.1
1999-04-01	71.3
1999-07-01	71.3
1999-10-01	70.7
2000-01-01	70.9
2000-04-01	71.7
2000-07-01	71.9
2000-10-01	71.6
2001-01-01	70.8
2001-04-01	71.5
2001-07-01	71.7
2001-10-01	71.1
2002-01-01	70.8
2002-04-01	72.2
2002-07-01	72.4
2002-10-01	72.1
2003-01-01	72.4
2003-04-01	72.9
2003-07-01	73.2
2003-10-01	72.7
2004-01-01	72.4
2004-04-01	73.3
2004-07-01	73.3
2004-10-01	73
2005-01-01	73.1
2005-04-01	73.7
2005-07-01	73.5
2005-10-01	73.4
2006-01-01	73.5
2006-04-01	74
2006-07-01	74.3
2006-10-01	73.9
2007-01-01	73.7
2007-04-01	74.2
2007-07-01	74.7
2007-10-01	74.2
2008-01-01	74
2008-04-01	74.8
2008-07-01	74.7
2008-10-01	74
2009-01-01	72.8
2009-04-01	73.3
2009-07-01	73.5
2009-10-01	72.2
2010-01-01	71.3
2010-04-01	70.9
2010-07-01	70.5
2010-10-01	68.7
2011-01-01	66.9
2011-04-01	66.5
2011-07-01	65.3
2011-10-01	62.7
2012-01-01	61.3
2012-04-01	60.5
2012-07-01	59.8
2012-10-01	58.7
2013-01-01	57.5
2013-04-01	58.2
2013-07-01	58.4
2013-10-01	57.5
2014-01-01	57.2
2014-04-01	58.1
2014-07-01	58.8
2014-10-01	57.8
2015-01-01	57.6
2015-04-01	59.3
2015-07-01	60.3
2015-10-01	59.9
2016-01-01	59.8
2016-04-01	61.3
2016-07-01	62.0
2016-10-01	60.8
2017-01-01	61.0
2017-04-01	62.9
2017-07-01	64.1
2017-10-01	62.9
2018-01-01	63.0
2018-04-01	64.9