Quarter	Percent
1998-01-01	55.1
1998-04-01	56
1998-07-01	56.8
1998-10-01	56.1
1999-01-01	56.5
1999-04-01	55.3
1999-07-01	55.3
1999-10-01	55.8
2000-01-01	55.5
2000-04-01	55.7
2000-07-01	55.4
2000-10-01	54.3
2001-01-01	55.6
2001-04-01	54.9
2001-07-01	55
2001-10-01	55.5
2002-01-01	54.4
2002-04-01	55.3
2002-07-01	56.6
2002-10-01	57.3
2003-01-01	57.6
2003-04-01	58.4
2003-07-01	59
2003-10-01	59.9
2004-01-01	55.3
2004-04-01	56.4
2004-07-01	56.8
2004-10-01	57.1
2005-01-01	57.9
2005-04-01	58.9
2005-07-01	59.4
2005-10-01	59
2006-01-01	59
2006-04-01	59.3
2006-07-01	59.4
2006-10-01	59
2007-01-01	58.2
2007-04-01	58.6
2007-07-01	59.9
2007-10-01	59.6
2008-01-01	59.3
2008-04-01	59.2
2008-07-01	59.2
2008-10-01	59.1
2009-01-01	57.5
2009-04-01	57.9
2009-07-01	58
2009-10-01	57.6
2010-01-01	57
2010-04-01	56.7
2010-07-01	56.8
2010-10-01	55.8
2011-01-01	54.4
2011-04-01	54
2011-07-01	51.4
2011-10-01	49.6
2012-01-01	48.6
2012-04-01	48.1
2012-07-01	47.2
2012-10-01	46.8
2013-01-01	45.5
2013-04-01	46.6
2013-07-01	46.7
2013-10-01	45.1
2014-01-01	44.8
2014-04-01	44.2
2014-07-01	43.8
2014-10-01	43.1
2015-01-01	43.2
2015-04-01	44.5
2015-07-01	45.7
2015-10-01	46.3
2016-01-01	45.4
2016-04-01	45.4
2016-07-01	47.3
2016-10-01	46.7
2017-01-01	47.5
2017-04-01	49.1
2017-07-01	50.7
2017-10-01	50.9
2018-01-01	51.5
2018-04-01	52.8