Quarter	Percent
1999-01-01	62.2
1999-04-01	59.6
1999-07-01	55.1
1999-10-01	58
2000-01-01	63.1
2000-04-01	62.7
2000-07-01	56.6
2000-10-01	61
2001-01-01	63.7
2001-04-01	64
2001-07-01	60
2001-10-01	63.7
2002-01-01	62.9
2002-04-01	63.4
2002-07-01	61.8
2002-10-01	65.5
2003-01-01	65.8
2003-04-01	66.2
2003-07-01	64.5
2003-10-01	62.6
2004-01-01	61.7
2004-04-01	60.7
2004-07-01	56.5
2004-10-01	59.7
2005-01-01	59.7
2005-04-01	63.5
2005-07-01	55.8
2005-10-01	58.9
2006-01-01	60.9
2006-04-01	58.7
2006-07-01	56
2006-10-01	61.9
2007-01-01	61
2007-04-01	59.6
2007-07-01	52.9
2007-10-01	59.2
2008-01-01	60.6
2008-04-01	58.9
2008-07-01	50.5
2008-10-01	58.5
2009-01-01	63.5
2009-04-01	60.4
2009-07-01	52.5
2009-10-01	60.2
2010-01-01	60.8
2010-04-01	60.9
2010-07-01	58.1
2010-10-01	60.5
2011-01-01	64.8
2011-04-01	64.4
2011-07-01	59.8
2011-10-01	61.4
2012-01-01	65.5
2012-04-01	68.8
2012-07-01	63
2012-10-01	65.2
2013-01-01	67.8
2013-04-01	66.1
2013-07-01	62.3
2013-10-01	68.4
2014-01-01	69.7
2014-04-01	67
2014-07-01	63.7
2014-10-01	65.2
2015-01-01	67.8
2015-04-01	64.5
2015-07-01	61.2
2015-10-01	65.1
2016-01-01	68.7
2016-04-01	67.7
2016-07-01	63.2
2016-10-01	65.5
2017-01-01	64.2
2017-04-01	61.7
2017-07-01	55.6
2017-10-01	61.9
2018-01-01	62.1
2018-04-01	59.7