Quarter	Percent
1998-01-01	42.7
1998-04-01	42.9
1998-07-01	43.3
1998-10-01	43.2
1999-01-01	44.2
1999-04-01	43.9
1999-07-01	43.6
1999-10-01	43.6
2000-01-01	43.6
2000-04-01	43.9
2000-07-01	44.1
2000-10-01	43.7
2001-01-01	43.6
2001-04-01	43.2
2001-07-01	43.1
2001-10-01	42.7
2002-01-01	43.5
2002-04-01	44.2
2002-07-01	44.7
2002-10-01	44.6
2003-01-01	44.7
2003-04-01	45.1
2003-07-01	45.5
2003-10-01	45.5
2004-01-01	46.4
2004-04-01	46.8
2004-07-01	46.9
2004-10-01	46.9
2005-01-01	46.6
2005-04-01	47.1
2005-07-01	47.2
2005-10-01	47.3
2006-01-01	47.4
2006-04-01	47.5
2006-07-01	47.9
2006-10-01	47.5
2007-01-01	47.5
2007-04-01	47.8
2007-07-01	47.7
2007-10-01	47.5
2008-01-01	47.5
2008-04-01	47.9
2008-07-01	48
2008-10-01	48.2
2009-01-01	48.8
2009-04-01	49.3
2009-07-01	49.7
2009-10-01	49.6
2010-01-01	49.9
2010-04-01	50.3
2010-07-01	50.4
2010-10-01	50.3
2011-01-01	50.1
2011-04-01	49.9
2011-07-01	50
2011-10-01	50.4
2012-01-01	50.4
2012-04-01	50.5
2012-07-01	50.7
2012-10-01	50.7
2013-01-01	50.3
2013-04-01	50.8
2013-07-01	50.7
2013-10-01	50.4
2014-01-01	50.8
2014-04-01	51.1
2014-07-01	51.3
2014-10-01	51.2
2015-01-01	51.4
2015-04-01	52.0
2015-07-01	52.3
2015-10-01	52.2
2016-01-01	52.2
2016-04-01	52.5
2016-07-01	52.7
2016-10-01	51.9
2017-01-01	52.0
2017-04-01	52.6
2017-07-01	52.1
2017-10-01	51.5
2018-01-01	51.2
2018-04-01	52.1