Quarter	Percent
1998-01-01	75.4
1998-04-01	76
1998-07-01	76
1998-10-01	76.1
1999-01-01	75.7
1999-04-01	75.6
1999-07-01	75.9
1999-10-01	76.1
2000-01-01	76.1
2000-04-01	76.2
2000-07-01	76.8
2000-10-01	77.1
2001-01-01	77
2001-04-01	76.9
2001-07-01	77
2001-10-01	77
2002-01-01	77
2002-04-01	76.9
2002-07-01	76.8
2002-10-01	75.5
2003-01-01	74.9
2003-04-01	75
2003-07-01	75.1
2003-10-01	74.7
2004-01-01	74.4
2004-04-01	74.3
2004-07-01	73.9
2004-10-01	73.5
2005-01-01	73.3
2005-04-01	73.3
2005-07-01	73.3
2005-10-01	73.2
2006-01-01	73.6
2006-04-01	73.8
2006-07-01	74
2006-10-01	73.4
2007-01-01	73.3
2007-04-01	73.4
2007-07-01	73.9
2007-10-01	74
2008-01-01	74
2008-04-01	74.1
2008-07-01	73.7
2008-10-01	73.4
2009-01-01	71.8
2009-04-01	71.4
2009-07-01	70.2
2009-10-01	70
2010-01-01	69.9
2010-04-01	69.7
2010-07-01	69.8
2010-10-01	69.5
2011-01-01	68.3
2011-04-01	68.2
2011-07-01	68.3
2011-10-01	66.1
2012-01-01	65.2
2012-04-01	65.2
2012-07-01	64.5
2012-10-01	63.1
2013-01-01	62
2013-04-01	63.2
2013-07-01	64.2
2013-10-01	64.5
2014-01-01	64.3
2014-04-01	65.8
2014-07-01	66.9
2014-10-01	66.1
2015-01-01	65.8
2015-04-01	66.8
2015-07-01	67.4
2015-10-01	67.5
2016-01-01	66.6
2016-04-01	68.3
2016-07-01	69.3
2016-10-01	68.8
2017-01-01	69.4
2017-04-01	70.8
2017-07-01	72.0
2017-10-01	72.2
2018-01-01	71.9
2018-04-01	72.6