Quarter	Percent
1998-01-01	70.1
1999-01-01	69.3
1999-04-01	70.2
1999-07-01	71.2
1999-10-01	73
2000-01-01	68.6
2000-04-01	69.3
2000-07-01	70.6
2000-10-01	69.6
2001-01-01	71
2001-04-01	69.1
2001-07-01	70.2
2001-10-01	69.1
2002-01-01	70.3
2002-04-01	69.2
2002-07-01	69
2002-10-01	68.5
2003-01-01	69
2003-04-01	67.3
2003-07-01	68
2003-10-01	67.7
2004-01-01	72.8
2004-04-01	71.4
2004-07-01	71.7
2004-10-01	70.8
2005-01-01	70.3
2005-04-01	69
2005-07-01	68.3
2005-10-01	67.8
2006-01-01	66.5
2006-04-01	65.6
2006-07-01	65.6
2006-10-01	64.9
2007-01-01	64.2
2007-04-01	62.3
2007-07-01	62.2
2007-10-01	62.3
2008-01-01	60.3
2008-04-01	60.1
2008-07-01	60.3
2008-10-01	60.4
2009-01-01	60.7
2009-04-01	59.6
2009-07-01	59
2009-10-01	58.6
2010-01-01	58.1
2010-04-01	57.6
2010-07-01	56.9
2010-10-01	58.5
2011-01-01	58.8
2011-04-01	58.2
2011-07-01	58.3
2011-10-01	58.9
2012-01-01	58.9
2012-04-01	56.7
2012-07-01	56.1
2012-10-01	55.9
2013-01-01	56.1
2013-04-01	54
2013-07-01	54.1
2013-10-01	53.8
2014-01-01	54.7
2014-04-01	52.6
2014-07-01	52.8
2014-10-01	52.3
2015-01-01	52.6
2015-04-01	51.8
2015-07-01	51.1
2015-10-01	50.3
2016-01-01	49.6
2016-04-01	47.8
2016-07-01	47.9
2016-10-01	47.8
2017-01-01	47.7
2017-04-01	46.8
2017-07-01	46.1
2017-10-01	45.2
2018-01-01	44.6
2018-04-01	44.4