Quarter	Percent
1998-01-01	57.0
1998-04-01	57.8
1998-07-01	57.4
1998-10-01	57.6
1999-01-01	57.6
1999-04-01	57.9
1999-07-01	58
1999-10-01	58.1
2000-01-01	58.3
2000-04-01	58.5
2000-07-01	58.8
2000-10-01	58.9
2001-01-01	59
2001-04-01	59.1
2001-07-01	59.1
2001-10-01	59.2
2002-01-01	59.1
2002-04-01	59.2
2002-07-01	59.1
2002-10-01	58.2
2003-01-01	58.2
2003-04-01	58.2
2003-07-01	58.1
2003-10-01	57.8
2004-01-01	57.6
2004-04-01	57.7
2004-07-01	57.5
2004-10-01	57.4
2005-01-01	57
2005-04-01	57.4
2005-07-01	57.2
2005-10-01	57.1
2006-01-01	57.1
2006-04-01	57.6
2006-07-01	57.6
2006-10-01	57
2007-01-01	57
2007-04-01	57.2
2007-07-01	57.6
2007-10-01	57.3
2008-01-01	57.4
2008-04-01	57.7
2008-07-01	57.3
2008-10-01	57
2009-01-01	56.2
2009-04-01	55.9
2009-07-01	55.1
2009-10-01	55.1
2010-01-01	55.1
2010-04-01	54.8
2010-07-01	54.5
2010-10-01	54.2
2011-01-01	53.2
2011-04-01	53.5
2011-07-01	53
2011-10-01	51.6
2012-01-01	51.2
2012-04-01	51.4
2012-07-01	51
2012-10-01	49.6
2013-01-01	48.8
2013-04-01	49.6
2013-07-01	50.2
2013-10-01	50.2
2014-01-01	49.8
2014-04-01	50.8
2014-07-01	51.4
2014-10-01	50.6
2015-01-01	50.5
2015-04-01	51.7
2015-07-01	51.6
2015-10-01	51.5
2016-01-01	50.9
2016-04-01	51.9
2016-07-01	52.6
2016-10-01	52.4
2017-01-01	52.6
2017-04-01	53.8
2017-07-01	54.3
2017-10-01	54.3
2018-01-01	54.3
2018-04-01	55.1