Quarter	Percent
1999-01-01	66.8
1999-04-01	66.1
1999-07-01	67
1999-10-01	68
2000-01-01	66.8
2000-04-01	66.5
2000-07-01	62.7
2000-10-01	65.5
2001-01-01	63.3
2001-04-01	65.2
2001-07-01	61.6
2001-10-01	59.9
2002-01-01	61.4
2002-04-01	61.6
2002-07-01	64.4
2002-10-01	65.8
2003-01-01	66.5
2003-04-01	66.8
2003-07-01	66.8
2003-10-01	61.9
2004-01-01	60.3
2004-04-01	57.3
2004-07-01	56.5
2004-10-01	55.8
2005-01-01	56.9
2005-04-01	55
2005-07-01	52.5
2005-10-01	54
2006-01-01	53
2006-04-01	53.6
2006-07-01	55.4
2006-10-01	54.9
2007-01-01	57.4
2007-04-01	52
2007-07-01	51.1
2007-10-01	53
2008-01-01	55.1
2008-04-01	52
2008-07-01	53.5
2008-10-01	53.9
2009-01-01	54.3
2009-04-01	50.1
2009-07-01	51
2009-10-01	51.8
2010-01-01	51.4
2010-04-01	53.1
2010-07-01	51.1
2010-10-01	54.2
2011-01-01	58.1
2011-04-01	57.2
2011-07-01	56.2
2011-10-01	57.8
2012-01-01	57.7
2012-04-01	57.4
2012-07-01	56
2012-10-01	54.4
2013-01-01	55.3
2013-04-01	54.8
2013-07-01	54.1
2013-10-01	55.3
2014-01-01	57.3
2014-04-01	53.7
2014-07-01	53.2
2014-10-01	53
2015-01-01	55.0
2015-04-01	51.9
2015-07-01	53.2
2015-10-01	54.5
2016-01-01	54.8
2016-04-01	51.9
2016-07-01	53.1
2016-10-01	51.8
2017-01-01	50.2
2017-04-01	47.7
2017-07-01	47.4
2017-10-01	47.6
2018-01-01	47.9
2018-04-01	44.8