Quarter	Percent
1998-04-01	27.9
1998-10-01	26.8
1999-04-01	26.5
1999-10-01	26.8
2000-04-01	25.8
2000-10-01	27.9
2001-04-01	30.0
2001-10-01	31.2
2002-01-01	32.3
2002-04-01	36.7
2002-07-01	36.3
2002-10-01	37.4
2003-01-01	36.0
2003-04-01	36.6
2003-07-01	42.2
2003-10-01	38.0
2004-01-01	41.7
2004-04-01	40.2
2004-07-01	40.7
2004-10-01	42.2
2005-01-01	41.9
2005-04-01	43.2
2005-07-01	46.6
2005-10-01	46.5
2006-01-01	48.2
2006-04-01	48.6
2006-07-01	50.8
2006-10-01	49.1
2007-01-01	53.4
2007-04-01	53.7
2007-07-01	53.5
2007-10-01	53.1
2008-01-01	55.3
2008-04-01	57.4
2008-07-01	56.1
2008-10-01	56.4
2009-01-01	57.8
2009-04-01	56.4
2009-07-01	48.7
2009-10-01	49.3
2010-01-01	49.6
2010-04-01	50.3
2010-07-01	47.0
2010-10-01	46.8
2011-01-01	47.3
2011-04-01	50.3
2011-07-01	49.4
2011-10-01	51.7
2012-01-01	50.6
2012-04-01	52.2
2012-07-01	54.2
2012-10-01	52.8
2013-01-01	54.4
2013-04-01	55.0
2013-07-01	55.2
2013-10-01	53.6
2014-01-01	57.8
2014-04-01	56.7
2014-07-01	55.3
2014-10-01	55.8
2015-01-01	57.2
2015-04-01	59.2
2015-07-01	60.1
2015-10-01	59.0
2016-01-01	59.0
2016-04-01	63.6
2016-07-01	60.6
2016-10-01	62.4
2017-01-01	60.6
2017-04-01	62.4
2017-07-01	62.4
2017-10-01	63.2
2018-01-01	62.3
2018-04-01	64.2