Quarter	Percent
1986-01-01	77.4
1986-04-01	76.6
1986-07-01	76
1986-10-01	76
1987-01-01	76.3
1987-04-01	75.2
1987-07-01	74.9
1987-10-01	74.8
1988-01-01	73.3
1988-04-01	72
1988-07-01	70.3
1988-10-01	71.0
1989-01-01	70.2
1989-04-01	69
1989-07-01	68.5
1989-10-01	69.5
1990-01-01	68.9
1990-04-01	68.2
1990-07-01	67.5
1990-10-01	67.8
1991-01-01	66.6
1991-04-01	65.8
1991-07-01	64.7
1991-10-01	65.2
1992-01-01	65.3
1992-04-01	65
1992-07-01	64.2
1992-10-01	65.1
1993-01-01	65.2
1993-04-01	65.4
1993-07-01	65.1
1993-10-01	66.5
1994-01-01	66.5
1994-04-01	66.9
1994-07-01	67.1
1994-10-01	68.3
1995-01-01	69
1995-04-01	69.1
1995-07-01	69
1995-10-01	70.3
1996-01-01	69.9
1996-04-01	69.6
1996-07-01	69.5
1996-10-01	70.1
1997-01-01	69.6
1997-04-01	69.1
1997-07-01	68.8
1997-10-01	69.5
1998-01-01	68.8
1998-04-01	67.7
1998-07-01	67.1
1998-10-01	67.7
1999-01-01	67.9
1999-04-01	67.4
1999-07-01	67.6
1999-10-01	69.4
2000-01-01	68.9
2000-04-01	68.3
2000-07-01	68.6
2000-10-01	70
2001-01-01	69.8
2001-04-01	69.1
2001-07-01	69.6
2001-10-01	70.6
2002-01-01	71.3
2002-04-01	70.4
2002-07-01	70.0
2002-10-01	71.0
2003-01-01	70.6
2003-04-01	69.9
2003-07-01	70.3
2003-10-01	71.0
2004-01-01	71.3
2004-04-01	71.5
2004-07-01	71.4
2004-10-01	73.1
2005-01-01	72.4
2005-04-01	71.6
2005-07-01	72.2
2005-10-01	73.3
2006-01-01	72.9
2006-04-01	72.7
2006-07-01	72.4
2006-10-01	73.5
2007-01-01	73.1
2007-04-01	72.8
2007-07-01	72.8
2007-10-01	73.4
2008-01-01	72
2008-04-01	72.1
2008-07-01	71.4
2008-10-01	72.9
2009-01-01	70.8
2009-04-01	70.7
2009-07-01	68.9
2009-10-01	69.9
2010-01-01	69.8
2010-04-01	69.3
2010-07-01	69.9
2010-10-01	70.0
2011-01-01	70.1
2011-04-01	69.6
2011-07-01	69.7
2011-10-01	70.2
2012-01-01	70.1
2012-04-01	69.2
2012-07-01	68.3
2012-10-01	68.6
2013-01-01	69.3
2013-04-01	69.1
2013-07-01	69.5
2013-10-01	70.8
2014-01-01	70.9
2014-04-01	70.7
2014-07-01	70.2
2014-10-01	71.4
2015-01-01	71.5
2015-04-01	70.9
2015-07-01	69.6
2015-10-01	70.8
2016-01-01	70.9
2016-04-01	71.6
2016-07-01	71.8
2016-10-01	72.7
2017-01-01	73.2
2017-04-01	72.3
2017-07-01	72.9
2017-10-01	73.6
2018-01-01	73.4
2018-04-01	72.7
2018-07-01	72.8