Quarter	Percent
1998-04-01	70.6
1999-01-01	68.8
1999-04-01	69.9
1999-07-01	63.4
1999-10-01	66.5
2000-01-01	71.7
2000-04-01	67.4
2000-07-01	65.8
2000-10-01	67.8
2001-01-01	70
2001-04-01	70
2001-07-01	64.6
2001-10-01	68.4
2002-01-01	69.4
2002-04-01	69.8
2002-07-01	64.8
2002-10-01	66.3
2003-01-01	68.4
2003-04-01	71.2
2003-07-01	67.4
2003-10-01	67.4
2004-01-01	67.2
2004-04-01	67.8
2004-07-01	65.5
2004-10-01	68.4
2005-01-01	67.5
2005-04-01	68.5
2005-07-01	68.7
2005-10-01	66.1
2006-01-01	68.3
2006-04-01	71.4
2006-07-01	65.8
2006-10-01	66.9
2007-01-01	69.2
2007-04-01	69
2007-07-01	67.8
2007-10-01	67.8
2008-01-01	70
2008-04-01	71.7
2008-07-01	66.8
2008-10-01	68.5
2009-01-01	72.1
2009-04-01	70.9
2009-07-01	67.9
2009-10-01	69.4
2010-01-01	69.9
2010-04-01	73
2010-07-01	68.3
2010-10-01	69.7
2011-01-01	70.3
2011-04-01	72
2011-07-01	68.9
2011-10-01	69.7
2012-01-01	72.8
2012-04-01	75.4
2012-07-01	70.3
2012-10-01	69.9
2013-01-01	73
2013-04-01	72.9
2013-07-01	69.6
2013-10-01	71.5
2014-01-01	73.1
2014-04-01	73
2014-07-01	70.1
2014-10-01	71.5
2015-01-01	72.7
2015-04-01	74.3
2015-07-01	72.2
2015-10-01	72.3
2016-01-01	73.1
2016-04-01	75.2
2016-07-01	73.0
2016-10-01	74.1
2017-01-01	76.2
2017-04-01	77.5
2017-07-01	72.0
2017-10-01	72.5
2018-01-01	72.9
2018-04-01	75.3