Quarter	Percent
1999-01-01	22.2
1999-04-01	21
1999-07-01	21
1999-10-01	20.5
2000-01-01	19.8
2000-04-01	18.8
2000-07-01	18.8
2000-10-01	17.9
2001-01-01	14.2
2001-04-01	13.6
2001-07-01	13.3
2001-10-01	13.7
2002-01-01	15.1
2002-04-01	14.6
2002-07-01	14.9
2002-10-01	14.7
2003-01-01	15.7
2003-04-01	14.6
2003-07-01	14.3
2003-10-01	14.1
2004-01-01	14.4
2004-04-01	13.8
2004-07-01	13
2004-10-01	13.2
2005-01-01	12.1
2005-04-01	10.5
2005-07-01	9.7
2005-10-01	10.4
2006-01-01	11.2
2006-04-01	10.2
2006-07-01	9.8
2006-10-01	10
2007-01-01	10
2007-04-01	9.1
2007-07-01	9.1
2007-10-01	9.8
2008-01-01	10.8
2008-04-01	10.7
2008-07-01	11.2
2008-10-01	13.6
2009-01-01	16.3
2009-04-01	16.5
2009-07-01	16
2009-10-01	17.5
2010-01-01	18.7
2010-04-01	18.9
2010-07-01	18.8
2010-10-01	19.3
2011-01-01	20.4
2011-04-01	19.6
2011-07-01	20.3
2011-10-01	21.7
2012-01-01	23.1
2012-04-01	22.6
2012-07-01	23.6
2012-10-01	24.8
2013-01-01	25.8
2013-04-01	25.3
2013-07-01	24.6
2013-10-01	25.2
2014-01-01	25.3
2014-04-01	23.9
2014-07-01	23.5
2014-10-01	23.5
2015-01-01	24.1
2015-04-01	22.9
2015-07-01	21.2
2015-10-01	21.4
2016-01-01	21.8
2016-04-01	20.7
2016-07-01	19.6
2016-10-01	19.2
2017-01-01	19.9
2017-04-01	18.1
2017-07-01	17.3
2017-10-01	17.4
2018-01-01	17.8
2018-04-01	16.3
2018-07-01	15.4