Quarter	Percent
1999-01-01	49.3
1999-04-01	49.6
1999-07-01	50.2
1999-10-01	51.1
2000-01-01	51.5
2000-04-01	51.8
2000-07-01	52.2
2000-10-01	52.5
2001-01-01	50.5
2001-04-01	50.4
2001-07-01	51
2001-10-01	51.5
2002-01-01	52.9
2002-04-01	53.7
2002-07-01	54.1
2002-10-01	54.5
2003-01-01	55
2003-04-01	55.5
2003-07-01	56.1
2003-10-01	56.5
2004-01-01	56.8
2004-04-01	57.1
2004-07-01	57.5
2004-10-01	58.1
2005-01-01	58.2
2005-04-01	59
2005-07-01	58.8
2005-10-01	59.5
2006-01-01	60.1
2006-04-01	60.7
2006-07-01	60.5
2006-10-01	61.4
2007-01-01	61.5
2007-04-01	61.7
2007-07-01	62
2007-10-01	62.4
2008-01-01	62.7
2008-04-01	63.4
2008-07-01	63.6
2008-10-01	64.6
2009-01-01	64.9
2009-04-01	65.1
2009-07-01	65.1
2009-10-01	65.3
2010-01-01	65.8
2010-04-01	66.1
2010-07-01	66.3
2010-10-01	66.7
2011-01-01	66.8
2011-04-01	67.6
2011-07-01	67.4
2011-10-01	67.5
2012-01-01	68.2
2012-04-01	68.3
2012-07-01	68.4
2012-10-01	68.6
2013-01-01	68.8
2013-04-01	68.7
2013-07-01	68.6
2013-10-01	68.9
2014-01-01	68.8
2014-04-01	68.8
2014-07-01	68.4
2014-10-01	69.2
2015-01-01	68.8
2015-04-01	69.5
2015-07-01	68.7
2015-10-01	69.2
2016-01-01	69.1
2016-04-01	69.5
2016-07-01	69.2
2016-10-01	69.0
2017-01-01	68.8
2017-04-01	68.8
2017-07-01	68.7
2017-10-01	69.0
2018-01-01	68.5
2018-04-01	68.9
2018-07-01	68.4