Quarter	Percent
1999-04-01	48.1
2000-01-01	46.2
2000-04-01	43.2
2000-07-01	46.1
2000-10-01	44.6
2001-01-01	43.8
2001-04-01	47
2001-07-01	48.4
2001-10-01	48.5
2002-01-01	48.5
2002-04-01	49.6
2002-07-01	50.4
2002-10-01	50.2
2003-01-01	50.1
2003-04-01	51
2003-07-01	48.5
2003-10-01	54
2004-01-01	55.6
2004-04-01	51.8
2004-07-01	51
2004-10-01	53.6
2005-01-01	54.4
2005-04-01	56.7
2005-07-01	55.8
2005-10-01	56
2006-01-01	58.4
2006-04-01	61.8
2006-07-01	57.7
2006-10-01	55.8
2007-01-01	59.7
2007-04-01	62.9
2007-07-01	58.5
2007-10-01	58.7
2008-01-01	61.3
2008-04-01	62.1
2008-07-01	62.1
2008-10-01	63.9
2009-01-01	62.6
2009-04-01	60.7
2009-07-01	58.7
2009-10-01	59.2
2010-01-01	54.2
2010-04-01	52.4
2010-07-01	53
2010-10-01	55.6
2011-01-01	56
2011-04-01	56.5
2011-07-01	58.2
2011-10-01	59.4
2012-01-01	60.3
2012-04-01	60.8
2012-07-01	61.1
2012-10-01	59.7
2013-01-01	62.9
2013-04-01	65.3
2013-07-01	61.7
2013-10-01	60.5
2014-01-01	59.5
2014-04-01	63.7
2014-07-01	66.5
2014-10-01	66.2
2015-01-01	61.8
2015-04-01	62.5
2015-07-01	68.6
2015-10-01	65.3
2016-01-01	61.7
2016-04-01	68.1
2016-07-01	68.1
2016-10-01	63.2
2017-01-01	66.7
2017-04-01	68.3
2017-07-01	67.7
2017-10-01	69.4
2018-01-01	67.7
2018-04-01	66.8