Quarter	Percent
1993-04-01	12.430
1993-07-01	12.738
1993-10-01	13.187
1994-01-01	13.700
1994-04-01	13.400
1994-07-01	13.400
1994-10-01	14.100
1995-01-01	14.300
1995-04-01	13.300
1995-07-01	12.400
1995-10-01	12.400
1996-01-01	12.300
1996-04-01	11.200
1996-07-01	10.900
1996-10-01	10.900
1997-01-01	12.000
1997-04-01	11.400
1997-07-01	12.000
1997-10-01	11.800
1998-01-01	12.700
1998-04-01	12.200
1998-07-01	12.900
1998-10-01	12.700
1999-01-01	15.400
1999-04-01	15.900
1999-07-01	16.800
1999-10-01	17.200
2000-01-01	19.100
2000-04-01	19.100
2000-07-01	18.700
2000-10-01	18.200
2001-01-01	19.900
2001-04-01	19.400
2001-07-01	19.100
2001-10-01	18.800
2002-01-01	19.500
2002-04-01	18.700
2002-07-01	18.400
2002-10-01	18.100
2003-01-01	18.500
2003-04-01	17.100
2003-07-01	17.100
2003-10-01	17.500
2004-01-01	19.500
2004-04-01	18.600
2004-07-01	17.600
2004-10-01	17.300
2005-01-01	17.600
2005-04-01	16.300
2005-07-01	15.700
2005-10-01	15.400
2006-01-01	15.000
2006-04-01	13.500
2006-07-01	12.900
2006-10-01	12.100
2007-01-01	11.700
2007-04-01	11.200
2007-07-01	11.300
2007-10-01	10.400
2008-01-01	10.500
2008-04-01	10.000
2008-07-01	8.900
2008-10-01	8.600
2009-01-01	10.400
2009-04-01	11.300
2009-07-01	12.500
2009-10-01	13.900
2010-01-01	15.200
2010-04-01	14.400
2010-07-01	14.100
2010-10-01	13.900
2011-01-01	14.000
2011-04-01	13.200
2011-07-01	13.200
2011-10-01	14.100
2012-01-01	14.100
2012-04-01	13.600
2012-07-01	13.700
2012-10-01	14.400
2013-01-01	14.500
2013-04-01	14.000
2013-07-01	14.100
2013-10-01	14.300
2014-01-01	14.100
2014-04-01	13.200
2014-07-01	12.900
2014-10-01	12.600
2015-01-01	12.400
2015-04-01	11.200
2015-07-01	11.300
2015-10-01	11.000
2016-01-01	10.400
2016-04-01	9.600
2016-07-01	9.500
2016-10-01	9.100
2017-01-01	8.700
2017-04-01	8.100
2017-07-01	8.000
2017-10-01	7.700
2018-01-01	7.100
2018-04-01	6.600