Quarter	Percent
1999-04-01	46.9
2000-04-01	46.2
2001-04-01	46.1
2002-04-01	47.1
2003-04-01	47.7
2004-04-01	49.8
2005-01-01	52.6
2005-04-01	52.9
2005-07-01	54
2005-10-01	54.7
2006-01-01	53.9
2006-04-01	56.2
2006-07-01	57
2006-10-01	57.3
2007-01-01	57.6
2007-04-01	59.7
2007-07-01	60
2007-10-01	60.4
2008-01-01	60
2008-04-01	62
2008-07-01	62.2
2008-10-01	62.6
2009-01-01	62.2
2009-04-01	64.4
2009-07-01	63.4
2009-10-01	65
2010-01-01	65.0
2010-04-01	65.0
2010-07-01	65.0
2010-10-01	65.8
2011-01-01	65.5
2011-04-01	67.2
2011-07-01	67.2
2011-10-01	68.5
2012-01-01	67.3
2012-04-01	68.1
2012-07-01	69.2
2012-10-01	69.8
2013-01-01	68.4
2013-04-01	69.6
2013-07-01	70.5
2013-10-01	71.1
2014-01-01	70.9
2014-04-01	70.9
2014-07-01	71.8
2014-10-01	71.9
2015-01-01	70.3
2015-04-01	70.4
2015-07-01	72.2
2015-10-01	72.4
2016-01-01	73.0
2016-04-01	73.4
2016-07-01	73.8
2016-10-01	74.6
2017-01-01	73.2
2017-04-01	75.1
2017-07-01	75.6
2017-10-01	76.1
2018-01-01	75.0
2018-04-01	75.6