Quarter	Percent
1999-04-01	37.8
2000-04-01	37.4
2001-04-01	37.7
2002-04-01	38.4
2003-04-01	39.4
2004-04-01	41.4
2005-01-01	44.6
2005-04-01	45
2005-07-01	45.6
2005-10-01	46.7
2006-01-01	46.4
2006-04-01	47.9
2006-07-01	48.7
2006-10-01	49.6
2007-01-01	49.4
2007-04-01	51.8
2007-07-01	51.7
2007-10-01	52.3
2008-01-01	52.4
2008-04-01	53.9
2008-07-01	54.1
2008-10-01	54.6
2009-01-01	54.8
2009-04-01	56.7
2009-07-01	55.8
2009-10-01	57
2010-01-01	57.7
2010-04-01	57.5
2010-07-01	57.9
2010-10-01	58.1
2011-01-01	58.8
2011-04-01	60
2011-07-01	60.4
2011-10-01	60.9
2012-01-01	60.6
2012-04-01	61.2
2012-07-01	62.2
2012-10-01	62.4
2013-01-01	62.3
2013-04-01	63.2
2013-07-01	64.2
2013-10-01	64.7
2014-01-01	64.8
2014-04-01	65.3
2014-07-01	66.1
2014-10-01	66
2015-01-01	65.3
2015-04-01	65.7
2015-07-01	66.7
2015-10-01	67.0
2016-01-01	67.8
2016-04-01	68.4
2016-07-01	68.9
2016-10-01	69.2
2017-01-01	68.8
2017-04-01	70.2
2017-07-01	70.5
2017-10-01	71.1
2018-01-01	70.5
2018-04-01	70.8