Quarter	Percent
1998-04-01	29.6
1998-10-01	28.7
1999-04-01	29.4
1999-10-01	28.7
2000-04-01	28.0
2000-10-01	30.4
2001-04-01	32.5
2001-10-01	33.6
2002-01-01	35.1
2002-04-01	39.5
2002-07-01	38.6
2002-10-01	41.3
2003-01-01	37.4
2003-04-01	40.4
2003-07-01	44.9
2003-10-01	42.8
2004-01-01	45.5
2004-04-01	45.9
2004-07-01	45.3
2004-10-01	46.7
2005-01-01	47.3
2005-04-01	44.9
2005-07-01	49.7
2005-10-01	50.0
2006-01-01	51.5
2006-04-01	50.4
2006-07-01	55.3
2006-10-01	51.2
2007-01-01	55.9
2007-04-01	56.0
2007-07-01	55.1
2007-10-01	55.7
2008-01-01	58.9
2008-04-01	59.6
2008-07-01	58.0
2008-10-01	60.4
2009-01-01	62.8
2009-04-01	64.0
2009-07-01	55.0
2009-10-01	56.2
2010-01-01	57.0
2010-04-01	57.5
2010-07-01	55.4
2010-10-01	52.9
2011-01-01	54.9
2011-04-01	57.9
2011-07-01	56.5
2011-10-01	59.1
2012-01-01	60.2
2012-04-01	61.5
2012-07-01	62.2
2012-10-01	59.5
2013-01-01	59.2
2013-04-01	62.4
2013-07-01	60.8
2013-10-01	59.6
2014-01-01	63.9
2014-04-01	61.9
2014-07-01	60.8
2014-10-01	60.1
2015-01-01	63.1
2015-04-01	63.3
2015-07-01	64.7
2015-10-01	63.0
2016-01-01	65.4
2016-04-01	68.4
2016-07-01	63.8
2016-10-01	66.7
2017-01-01	65.0
2017-04-01	67.7
2017-07-01	67.1
2017-10-01	67.7
2018-01-01	67.7
2018-04-01	69.9