Quarter	Percent
1997-01-01	11.6
1997-04-01	10.9
1997-07-01	9.5
1997-10-01	9.4
1998-01-01	10.5
1998-04-01	10.4
1998-07-01	9.2
1998-10-01	9.5
1999-01-01	11.8
1999-04-01	12.9
1999-07-01	12.3
1999-10-01	13
2000-01-01	16.9
2000-04-01	15
2000-07-01	15.3
2000-10-01	16.2
2001-01-01	14.7
2001-04-01	13
2001-07-01	13.5
2001-10-01	13.8
2002-01-01	13.2
2002-04-01	11.3
2002-07-01	10
2002-10-01	14.8
2003-01-01	12.9
2003-04-01	12.1
2003-07-01	9.7
2003-10-01	8.5
2004-01-01	11.4
2004-04-01	11.6
2004-07-01	11.6
2004-10-01	9.8
2005-01-01	11.6
2005-04-01	10.7
2005-07-01	6.8
2005-10-01	7.6
2006-01-01	7.7
2006-04-01	6.2
2006-07-01	5.0
2006-10-01	6.1
2007-01-01	6.7
2007-04-01	5.7
2007-07-01	4.7
2007-10-01	4.5
2008-01-01	3.6
2008-04-01	4.4
2008-07-01	6.9
2008-10-01	8.1
2009-01-01	13.6
2009-04-01	16.6
2009-07-01	16.9
2009-10-01	19.7
2010-01-01	24.8
2010-04-01	22.3
2010-07-01	15.9
2010-10-01	14.1
2011-01-01	15.4
2011-04-01	14
2011-07-01	10.5
2011-10-01	12.4
2012-01-01	12.7
2012-04-01	11.6
2012-07-01	9.5
2012-10-01	9.9
2013-01-01	10.8
2013-04-01	8.1
2013-07-01	8.1
2013-10-01	9.3
2014-01-01	9.4
2014-04-01	7.8
2014-07-01	8.1
2014-10-01	6.1
2015-01-01	7.6
2015-04-01	6.5
2015-07-01	4.7
2015-10-01	6.3
2016-01-01	7.4
2016-04-01	7.6
2016-07-01	7.5
2016-10-01	7.2
2017-01-01	5.9
2017-04-01	7.7
2017-07-01	5.8
2017-10-01	5.3
2018-01-01	7.5
2018-04-01	5.3