Quarter	Percent
1999-04-01	39.6
2000-01-01	39.1
2000-04-01	39.9
2000-07-01	37.4
2000-10-01	40.6
2001-01-01	40.2
2001-04-01	42.3
2001-07-01	42.7
2001-10-01	44.3
2002-01-01	43.2
2002-04-01	47.3
2002-07-01	49.5
2002-10-01	48
2003-01-01	47.9
2003-04-01	49.2
2003-07-01	45.7
2003-10-01	48.5
2004-01-01	56.3
2004-04-01	53.6
2004-07-01	49.5
2004-10-01	49.7
2005-01-01	53.6
2005-04-01	56.6
2005-07-01	56.1
2005-10-01	54
2006-01-01	56.2
2006-04-01	63.8
2006-07-01	59.5
2006-10-01	57.9
2007-01-01	62.1
2007-04-01	65.2
2007-07-01	58.9
2007-10-01	56.5
2008-01-01	58.7
2008-04-01	61.5
2008-07-01	60.2
2008-10-01	61.7
2009-01-01	62.1
2009-04-01	60.1
2009-07-01	60.9
2009-10-01	61.5
2010-01-01	57.7
2010-04-01	56.4
2010-07-01	53.9
2010-10-01	53.1
2011-01-01	56.8
2011-04-01	59.2
2011-07-01	56.8
2011-10-01	58.5
2012-01-01	63.6
2012-04-01	64.1
2012-07-01	61.5
2012-10-01	56.8
2013-01-01	64.5
2013-04-01	67.9
2013-07-01	61.8
2013-10-01	60
2014-01-01	59.3
2014-04-01	62.5
2014-07-01	66.1
2014-10-01	64.5
2015-01-01	61.0
2015-04-01	64.8
2015-07-01	71.5
2015-10-01	65.6
2016-01-01	62.7
2016-04-01	68.9
2016-07-01	68.8
2016-10-01	65.5
2017-01-01	67.2
2017-04-01	68.0
2017-07-01	69.0
2017-10-01	72.9
2018-01-01	72.5
2018-04-01	69.5