Quarter	Percent
1999-01-01	71.6
1999-04-01	73.3
1999-07-01	74.6
1999-10-01	69.8
2000-01-01	70.1
2000-04-01	71.9
2000-07-01	71.5
2000-10-01	69.4
2001-01-01	67.9
2001-04-01	67.2
2001-07-01	71.7
2001-10-01	65.3
2002-01-01	66.6
2002-04-01	68.8
2002-07-01	70.8
2002-10-01	68.1
2003-01-01	63.7
2003-04-01	65.9
2003-07-01	69.3
2003-10-01	63.6
2004-01-01	67.6
2004-04-01	66.4
2004-07-01	71.6
2004-10-01	65.9
2005-01-01	67.6
2005-04-01	67.2
2005-07-01	69.5
2005-10-01	68.2
2006-01-01	68
2006-04-01	69
2006-07-01	73.2
2006-10-01	69.6
2007-01-01	71.4
2007-04-01	72.4
2007-07-01	71.1
2007-10-01	67.6
2008-01-01	68.1
2008-04-01	73.5
2008-07-01	74.1
2008-10-01	72.9
2009-01-01	71.8
2009-04-01	72.5
2009-07-01	72
2009-10-01	67.3
2010-01-01	67.1
2010-04-01	69.6
2010-07-01	68.1
2010-10-01	65.3
2011-01-01	67
2011-04-01	68.2
2011-07-01	68.7
2011-10-01	64.4
2012-01-01	63.6
2012-04-01	66
2012-07-01	65
2012-10-01	61.6
2013-01-01	61.8
2013-04-01	62
2013-07-01	63.5
2013-10-01	59.6
2014-01-01	59.5
2014-04-01	59.8
2014-07-01	64
2014-10-01	62.7
2015-01-01	61.0
2015-04-01	61.9
2015-07-01	63.7
2015-10-01	61.8
2016-01-01	64.9
2016-04-01	66.8
2016-07-01	68.0
2016-10-01	64.8
2017-01-01	62.8
2017-04-01	63.1
2017-07-01	65.3
2017-10-01	61.8
2018-01-01	62.0
2018-04-01	64.1