Quarter	Percent
1998-01-01	24.6
1998-04-01	25.4
1998-07-01	27
1998-10-01	25.7
1999-01-01	24.9
1999-04-01	25.5
1999-07-01	27.1
1999-10-01	25.5
2000-01-01	25.4
2000-04-01	26.1
2000-07-01	27.4
2000-10-01	27
2001-01-01	25.8
2001-04-01	26.2
2001-07-01	27
2001-10-01	26.2
2002-01-01	25.2
2002-04-01	25.7
2002-07-01	26.8
2002-10-01	25.5
2003-01-01	24.8
2003-04-01	25.4
2003-07-01	26.3
2003-10-01	24.3
2004-01-01	27.9
2004-04-01	27.7
2004-07-01	28.7
2004-10-01	26.5
2005-01-01	25.7
2005-04-01	26.2
2005-07-01	25.5
2005-10-01	25.3
2006-01-01	25.4
2006-04-01	25.6
2006-07-01	25.7
2006-10-01	24.5
2007-01-01	23.9
2007-04-01	25.1
2007-07-01	25.6
2007-10-01	23.6
2008-01-01	24.1
2008-04-01	25
2008-07-01	25
2008-10-01	22.8
2009-01-01	21.6
2009-04-01	21.6
2009-07-01	22.2
2009-10-01	20.8
2010-01-01	20.5
2010-04-01	20.2
2010-07-01	20.3
2010-10-01	20
2011-01-01	19.4
2011-04-01	18.7
2011-07-01	19.5
2011-10-01	19.2
2012-01-01	18.5
2012-04-01	18.7
2012-07-01	19.2
2012-10-01	17.4
2013-01-01	16
2013-04-01	16.7
2013-07-01	16.9
2013-10-01	15.5
2014-01-01	14.4
2014-04-01	15.7
2014-07-01	16.7
2014-10-01	15.5
2015-01-01	14.2
2015-04-01	15.1
2015-07-01	17.0
2015-10-01	16.2
2016-01-01	15.3
2016-04-01	17.2
2016-07-01	17.5
2016-10-01	16.2
2017-01-01	16.2
2017-04-01	16.8
2017-07-01	18.1
2017-10-01	17.2
2018-01-01	17.3
2018-04-01	17.7