Quarter	Percent
1998-01-01	47.7
1998-04-01	49.2
1998-07-01	49.5
1998-10-01	48.4
1999-01-01	49.7
1999-04-01	49.5
1999-07-01	49.0
1999-10-01	47
2000-01-01	48
2000-04-01	50.4
2000-07-01	47.9
2000-10-01	47.7
2001-01-01	48.2
2001-04-01	48.5
2001-07-01	46.4
2001-10-01	47.1
2002-01-01	47.3
2002-04-01	47.6
2002-07-01	46.3
2002-10-01	47.2
2003-01-01	49.6
2003-04-01	51.7
2003-07-01	50.9
2003-10-01	52
2004-01-01	52.8
2004-04-01	52.9
2004-07-01	51.8
2004-10-01	53.3
2005-01-01	54.1
2005-04-01	53.7
2005-07-01	53.8
2005-10-01	54.3
2006-01-01	54.6
2006-04-01	54.1
2006-07-01	54.2
2006-10-01	55
2007-01-01	55
2007-04-01	56.3
2007-07-01	54.4
2007-10-01	55.6
2008-01-01	55.3
2008-04-01	56.3
2008-07-01	57
2008-10-01	57
2009-01-01	59
2009-04-01	59.9
2009-07-01	60.2
2009-10-01	60.5
2010-01-01	61.5
2010-04-01	62.5
2010-07-01	61.9
2010-10-01	62.2
2011-01-01	60.1
2011-04-01	61.3
2011-07-01	57.8
2011-10-01	59.2
2012-01-01	61.1
2012-04-01	61.5
2012-07-01	58.5
2012-10-01	62
2013-01-01	63.5
2013-04-01	64.8
2013-07-01	62
2013-10-01	64.8
2014-01-01	65.2
2014-04-01	66.7
2014-07-01	63.1
2014-10-01	66
2015-01-01	66.5
2015-04-01	67.5
2015-07-01	64.8
2015-10-01	64.3
2016-01-01	66.1
2016-04-01	65.7
2016-07-01	63.9
2016-10-01	64.2
2017-01-01	64.8
2017-04-01	65.8
2017-07-01	63.5
2017-10-01	63.7
2018-01-01	64.3
2018-04-01	65.1