Quarter	Percent
1983-01-01	13
1983-04-01	13
1983-07-01	13.2
1983-10-01	13.8
1984-01-01	14.9
1984-04-01	14.7
1984-07-01	14.8
1984-10-01	15.1
1985-01-01	16.3
1985-04-01	16
1985-07-01	16
1985-10-01	15.9
1986-01-01	16.5
1986-04-01	16
1986-07-01	15.8
1986-10-01	15.8
1987-01-01	16.4
1987-04-01	16
1987-07-01	15.7
1987-10-01	15.6
1988-01-01	16.3
1988-04-01	15.7
1988-07-01	15.5
1988-10-01	15.1
1989-01-01	15.3
1989-04-01	14.5
1989-07-01	14
1989-10-01	13.4
1990-01-01	13.5
1990-04-01	12.5
1990-07-01	12.7
1990-10-01	12.7
1991-01-01	13.8
1991-04-01	14
1991-07-01	14.5
1991-10-01	14.4
1992-01-01	15.1
1992-04-01	14.9
1992-07-01	15.1
1992-10-01	15.1
1993-01-01	15.8
1993-04-01	15.5
1993-07-01	15.3
1993-10-01	15
1994-01-01	15.2
1994-04-01	14.5
1994-07-01	13.9
1994-10-01	13.1
1995-01-01	12.8
1995-04-01	12.1
1995-07-01	12
1995-10-01	11.8
1996-01-01	12
1996-04-01	11.6
1996-07-01	11.6
1996-10-01	10.9
1997-01-01	10.7
1997-04-01	10.1
1997-07-01	9.7
1997-10-01	9.0
1998-01-01	8.6
1998-04-01	8.0
1998-07-01	7.5
1998-10-01	6.8
1999-01-01	6.5
1999-04-01	6.0
1999-07-01	5.6
1999-10-01	5.2
2000-01-01	4.8
2000-04-01	4.4
2000-07-01	4.4
2000-10-01	4.0
2001-01-01	3.8
2001-04-01	3.8
2001-07-01	4.4
2001-10-01	4.2
2002-01-01	4.7
2002-04-01	4.6
2002-07-01	4.8
2002-10-01	4.8
2003-01-01	5.0
2003-04-01	4.8
2003-07-01	5.4
2003-10-01	4.9
2004-01-01	4.8
2004-04-01	5.0
2004-07-01	5.1
2004-10-01	4.7
2005-01-01	4.5
2005-04-01	4.6
2005-07-01	4.8
2005-10-01	4.5
2006-01-01	4.4
2006-04-01	4.6
2006-07-01	5.0
2006-10-01	4.4
2007-01-01	4.9
2007-04-01	5.0
2007-07-01	5.0
2007-10-01	5.2
2008-01-01	6.0
2008-04-01	6.8
2008-07-01	8.3
2008-10-01	9.5
2009-01-01	13
2009-04-01	15.6
2009-07-01	15.9
2009-10-01	16.1
2010-01-01	16.7
2010-04-01	17.1
2010-07-01	17.2
2010-10-01	17.6
2011-01-01	17.6
2011-04-01	17.8
2011-07-01	18
2011-10-01	17.7
2012-01-01	18.1
2012-04-01	18.3
2012-07-01	17.9
2012-10-01	16.6
2013-01-01	15.8
2013-04-01	15.9
2013-07-01	14.8
2013-10-01	13.2
2014-01-01	13.7
2014-04-01	13.5
2014-07-01	12.5
2014-10-01	11.4
2015-01-01	11.4
2015-04-01	11.0
2015-07-01	10.6
2015-10-01	10.2
2016-01-01	9.8
2016-04-01	9.8
2016-07-01	9.1
2016-10-01	7.6
2017-01-01	7.3
2017-04-01	7.5
2017-07-01	7.1
2017-10-01	6.5
2018-01-01	5.8
2018-04-01	6.2