Quarter	Percent
1999-04-01	51.2
2000-01-01	53.5
2000-04-01	47.3
2000-07-01	51.2
2000-10-01	51.9
2001-01-01	48.5
2001-04-01	51.8
2001-07-01	53.7
2001-10-01	54.2
2002-01-01	53.3
2002-04-01	55.3
2002-07-01	55.4
2002-10-01	55.7
2003-01-01	54.5
2003-04-01	55.1
2003-07-01	53.2
2003-10-01	58
2004-01-01	58.6
2004-04-01	54.3
2004-07-01	54.6
2004-10-01	57.6
2005-01-01	59.3
2005-04-01	58.8
2005-07-01	58.7
2005-10-01	58.8
2006-01-01	59.8
2006-04-01	64.6
2006-07-01	60.2
2006-10-01	59.2
2007-01-01	63
2007-04-01	64.8
2007-07-01	59.7
2007-10-01	61.1
2008-01-01	63.5
2008-04-01	63.3
2008-07-01	64.4
2008-10-01	68.8
2009-01-01	67.2
2009-04-01	65.8
2009-07-01	66.3
2009-10-01	66.8
2010-01-01	64
2010-04-01	63.3
2010-07-01	64.6
2010-10-01	65.1
2011-01-01	66
2011-04-01	63.6
2011-07-01	63.1
2011-10-01	67.7
2012-01-01	66.3
2012-04-01	65.3
2012-07-01	65.2
2012-10-01	63.6
2013-01-01	67.1
2013-04-01	69.6
2013-07-01	65.6
2013-10-01	64.3
2014-01-01	63.8
2014-04-01	67.7
2014-07-01	70.1
2014-10-01	69
2015-01-01	66.4
2015-04-01	67.2
2015-07-01	72.4
2015-10-01	68.8
2016-01-01	67.2
2016-04-01	74.0
2016-07-01	73.6
2016-10-01	69.0
2017-01-01	71.1
2017-04-01	71.9
2017-07-01	72.2
2017-10-01	73.6
2018-01-01	72.6
2018-04-01	71.6