Quarter	Percent
1999-01-01	42.8
1999-04-01	43.1
1999-07-01	43.7
1999-10-01	44.4
2000-01-01	44.7
2000-04-01	45.1
2000-07-01	45.4
2000-10-01	45.6
2001-01-01	43.9
2001-04-01	43.9
2001-07-01	44.3
2001-10-01	44.7
2002-01-01	46.1
2002-04-01	46.9
2002-07-01	47.3
2002-10-01	47.6
2003-01-01	48.1
2003-04-01	48.6
2003-07-01	49.2
2003-10-01	49.5
2004-01-01	49.7
2004-04-01	50.1
2004-07-01	50.6
2004-10-01	51.2
2005-01-01	51.2
2005-04-01	51.9
2005-07-01	51.8
2005-10-01	52.4
2006-01-01	53
2006-04-01	53.6
2006-07-01	53.5
2006-10-01	54.4
2007-01-01	54.5
2007-04-01	54.8
2007-07-01	55.1
2007-10-01	55.5
2008-01-01	55.8
2008-04-01	56.4
2008-07-01	56.5
2008-10-01	57.5
2009-01-01	57.7
2009-04-01	58
2009-07-01	57.9
2009-10-01	58.2
2010-01-01	58.6
2010-04-01	58.9
2010-07-01	59
2010-10-01	59.3
2011-01-01	59.4
2011-04-01	60.1
2011-07-01	59.9
2011-10-01	60
2012-01-01	60.5
2012-04-01	60.6
2012-07-01	60.7
2012-10-01	60.7
2013-01-01	60.8
2013-04-01	60.7
2013-07-01	60.5
2013-10-01	60.6
2014-01-01	60.4
2014-04-01	60.3
2014-07-01	59.9
2014-10-01	60.5
2015-01-01	60.1
2015-04-01	60.7
2015-07-01	60.0
2015-10-01	60.5
2016-01-01	60.3
2016-04-01	60.6
2016-07-01	60.3
2016-10-01	60.0
2017-01-01	59.8
2017-04-01	59.8
2017-07-01	59.6
2017-10-01	59.9
2018-01-01	59.5
2018-04-01	59.9
2018-07-01	59.6