Quarter	Percent
1998-01-01	60.1
1998-04-01	60.8
1998-07-01	61.1
1998-10-01	60.4
1999-01-01	60
1999-04-01	60
1999-07-01	59.9
1999-10-01	59.3
2000-01-01	59.5
2000-04-01	60
2000-07-01	60.2
2000-10-01	59.8
2001-01-01	59.3
2001-04-01	59.7
2001-07-01	59.7
2001-10-01	59
2002-01-01	58.9
2002-04-01	60
2002-07-01	60.2
2002-10-01	59.9
2003-01-01	60.1
2003-04-01	60.5
2003-07-01	60.6
2003-10-01	60.2
2004-01-01	59.6
2004-04-01	60.4
2004-07-01	60.3
2004-10-01	60.1
2005-01-01	60
2005-04-01	60.5
2005-07-01	60.4
2005-10-01	60.3
2006-01-01	60.4
2006-04-01	60.7
2006-07-01	61
2006-10-01	60.6
2007-01-01	60.4
2007-04-01	60.8
2007-07-01	61.1
2007-10-01	60.8
2008-01-01	60.6
2008-04-01	61.2
2008-07-01	61.2
2008-10-01	60.5
2009-01-01	59.6
2009-04-01	59.9
2009-07-01	59.9
2009-10-01	58.9
2010-01-01	58.1
2010-04-01	57.6
2010-07-01	57.2
2010-10-01	55.8
2011-01-01	54.2
2011-04-01	53.8
2011-07-01	52.7
2011-10-01	50.4
2012-01-01	49.2
2012-04-01	48.5
2012-07-01	47.8
2012-10-01	46.8
2013-01-01	45.8
2013-04-01	46.2
2013-07-01	46.4
2013-10-01	45.6
2014-01-01	45.4
2014-04-01	46.1
2014-07-01	46.6
2014-10-01	45.7
2015-01-01	45.5
2015-04-01	46.8
2015-07-01	47.6
2015-10-01	47.3
2016-01-01	47.0
2016-04-01	48.2
2016-07-01	48.7
2016-10-01	47.8
2017-01-01	47.9
2017-04-01	49.4
2017-07-01	50.4
2017-10-01	49.4
2018-01-01	49.5
2018-04-01	50.9