Quarter	Percent
1983-01-01	13.5
1983-04-01	13.6
1983-07-01	14
1983-10-01	14.4
1984-01-01	15.4
1984-04-01	15.3
1984-07-01	15.5
1984-10-01	15.8
1985-01-01	16.9
1985-04-01	16.7
1985-07-01	17
1985-10-01	16.7
1986-01-01	17.2
1986-04-01	16.7
1986-07-01	16.9
1986-10-01	16.6
1987-01-01	17
1987-04-01	16.6
1987-07-01	16.6
1987-10-01	16.3
1988-01-01	16.8
1988-04-01	16.2
1988-07-01	16.2
1988-10-01	15.6
1989-01-01	15.6
1989-04-01	14.9
1989-07-01	14.6
1989-10-01	13.8
1990-01-01	13.9
1990-04-01	13.1
1990-07-01	13.5
1990-10-01	13.3
1991-01-01	14.3
1991-04-01	14.6
1991-07-01	15.3
1991-10-01	14.9
1992-01-01	15.3
1992-04-01	15.1
1992-07-01	15.7
1992-10-01	15.5
1993-01-01	16
1993-04-01	15.7
1993-07-01	15.7
1993-10-01	15.2
1994-01-01	15.3
1994-04-01	14.6
1994-07-01	14.3
1994-10-01	13.3
1995-01-01	12.8
1995-04-01	12.1
1995-07-01	12.2
1995-10-01	12
1996-01-01	12.1
1996-04-01	11.7
1996-07-01	11.8
1996-10-01	11
1997-01-01	10.7
1997-04-01	10.1
1997-07-01	9.8
1997-10-01	8.9
1998-01-01	8.4
1998-04-01	7.7
1998-07-01	7.5
1998-10-01	6.7
1999-01-01	6.3
1999-04-01	5.8
1999-07-01	5.8
1999-10-01	5.2
2000-01-01	4.8
2000-04-01	4.3
2000-07-01	4.4
2000-10-01	3.9
2001-01-01	3.7
2001-04-01	3.7
2001-07-01	4.3
2001-10-01	4.0
2002-01-01	4.4
2002-04-01	4.2
2002-07-01	4.6
2002-10-01	4.6
2003-01-01	4.6
2003-04-01	4.5
2003-07-01	5.3
2003-10-01	4.6
2004-01-01	4.4
2004-04-01	4.5
2004-07-01	4.8
2004-10-01	4.4
2005-01-01	4.1
2005-04-01	4.3
2005-07-01	4.6
2005-10-01	4.4
2006-01-01	4.2
2006-04-01	4.4
2006-07-01	4.9
2006-10-01	4.2
2007-01-01	4.9
2007-04-01	5.2
2007-07-01	5.1
2007-10-01	4.9
2008-01-01	5.3
2008-04-01	6.1
2008-07-01	7.6
2008-10-01	8.1
2009-01-01	10.8
2009-04-01	12.9
2009-07-01	13.6
2009-10-01	13.3
2010-01-01	13.7
2010-04-01	14.6
2010-07-01	14.9
2010-10-01	15.1
2011-01-01	15.0
2011-04-01	15.3
2011-07-01	15.9
2011-10-01	15.3
2012-01-01	15.8
2012-04-01	15.9
2012-07-01	15.9
2012-10-01	14.5
2013-01-01	14.4
2013-04-01	14.7
2013-07-01	13.7
2013-10-01	12.4
2014-01-01	12.7
2014-04-01	12.5
2014-07-01	12.0
2014-10-01	10.5
2015-01-01	10.5
2015-04-01	10.4
2015-07-01	9.9
2015-10-01	9.1
2016-01-01	8.8
2016-04-01	9.1
2016-07-01	8.6
2016-10-01	7.2
2017-01-01	7.1
2017-04-01	6.9
2017-07-01	6.9
2017-10-01	6.1
2018-01-01	5.7
2018-04-01	6.0