Quarter	Percent
1998-01-01	57
1998-04-01	56.5
1998-07-01	56.1
1998-10-01	56.6
1999-01-01	57.5
1999-04-01	57.2
1999-07-01	56.2
1999-10-01	56.2
2000-01-01	58
2000-04-01	57.8
2000-07-01	56.4
2000-10-01	56.7
2001-01-01	58.2
2001-04-01	58.8
2001-07-01	57.1
2001-10-01	56.6
2002-01-01	57.5
2002-04-01	57.1
2002-07-01	57
2002-10-01	56.7
2003-01-01	56.4
2003-04-01	55.6
2003-07-01	55.7
2003-10-01	54.7
2004-01-01	57.5
2004-04-01	56.2
2004-07-01	55.7
2004-10-01	54.9
2005-01-01	56.1
2005-04-01	56
2005-07-01	55.9
2005-10-01	54.9
2006-01-01	56.3
2006-04-01	55.2
2006-07-01	54.3
2006-10-01	54.4
2007-01-01	54.7
2007-04-01	53.9
2007-07-01	52.9
2007-10-01	53.6
2008-01-01	54.4
2008-04-01	53.3
2008-07-01	52.6
2008-10-01	52.3
2009-01-01	52.5
2009-04-01	51.4
2009-07-01	51.5
2009-10-01	50.9
2010-01-01	50.7
2010-04-01	50.7
2010-07-01	50.8
2010-10-01	49.7
2011-01-01	50
2011-04-01	50.2
2011-07-01	49.8
2011-10-01	47.8
2012-01-01	47.9
2012-04-01	46.4
2012-07-01	46.1
2012-10-01	45.3
2013-01-01	44.9
2013-04-01	44.4
2013-07-01	43
2013-10-01	41.3
2014-01-01	41.1
2014-04-01	40.1
2014-07-01	39.2
2014-10-01	38.7
2015-01-01	37.7
2015-04-01	36.2
2015-07-01	36.3
2015-10-01	36.6
2016-01-01	35.2
2016-04-01	33.9
2016-07-01	33.9
2016-10-01	33.6
2017-01-01	33.8
2017-04-01	33.0
2017-07-01	32.6
2017-10-01	32.4
2018-01-01	32.4
2018-04-01	31.2