Quarter	Percent
1999-04-01	60.9
2000-01-01	58.4
2000-04-01	58.7
2000-07-01	59.8
2000-10-01	58.5
2001-01-01	59.2
2001-04-01	59
2001-07-01	59.2
2001-10-01	60.2
2002-01-01	60.1
2002-04-01	59.5
2002-07-01	60.9
2002-10-01	58.6
2003-01-01	58.5
2003-04-01	61.3
2003-07-01	63.3
2003-10-01	63.1
2004-01-01	60.5
2004-04-01	61
2004-07-01	61.5
2004-10-01	61.8
2005-01-01	59.5
2005-04-01	61.1
2005-07-01	63.6
2005-10-01	63
2006-01-01	64.8
2006-04-01	66.7
2006-07-01	67.8
2006-10-01	67.5
2007-01-01	67.2
2007-04-01	68
2007-07-01	68.8
2007-10-01	68.5
2008-01-01	69.1
2008-04-01	68.6
2008-07-01	68.2
2008-10-01	67.7
2009-01-01	61.7
2009-04-01	59.2
2009-07-01	60.9
2009-10-01	57.5
2010-01-01	53.3
2010-04-01	54.5
2010-07-01	59.4
2010-10-01	61.6
2011-01-01	61.1
2011-04-01	61.5
2011-07-01	64.8
2011-10-01	63.4
2012-01-01	62.8
2012-04-01	63.7
2012-07-01	66.7
2012-10-01	65.8
2013-01-01	65.2
2013-04-01	67.3
2013-07-01	67.1
2013-10-01	65.5
2014-01-01	66
2014-04-01	68.3
2014-07-01	68.3
2014-10-01	68.9
2015-01-01	67.4
2015-04-01	69.8
2015-07-01	72.6
2015-10-01	69.5
2016-01-01	68.0
2016-04-01	70.7
2016-07-01	72.0
2016-10-01	69.8
2017-01-01	71.0
2017-04-01	71.4
2017-07-01	72.9
2017-10-01	73.1
2018-01-01	70.7
2018-04-01	72.9