Quarter	Percent
1999-01-01	49.6
2000-01-01	47
2000-04-01	47.5
2000-07-01	48
2000-10-01	47.4
2001-01-01	46.2
2001-04-01	46.4
2001-07-01	46.5
2001-10-01	45.5
2002-01-01	44.3
2002-04-01	44.6
2002-07-01	44.6
2002-10-01	44.1
2003-01-01	43.3
2003-04-01	44.1
2003-07-01	44.4
2003-10-01	44.2
2004-01-01	43.4
2004-04-01	44
2004-07-01	44.9
2004-10-01	45.1
2005-01-01	44.1
2005-04-01	44.6
2005-07-01	46
2005-10-01	45.9
2006-01-01	44.9
2006-04-01	46.1
2006-07-01	47.6
2006-10-01	47.5
2007-01-01	47.2
2007-04-01	48.4
2007-07-01	49.2
2007-10-01	49.5
2008-01-01	49.4
2008-04-01	50.1
2008-07-01	51
2008-10-01	51
2009-01-01	50
2009-04-01	50.4
2009-07-01	50.9
2009-10-01	50.4
2010-01-01	49.1
2010-04-01	50
2010-07-01	50.6
2010-10-01	50.2
2011-01-01	49.6
2011-04-01	50.3
2011-07-01	50.6
2011-10-01	50.3
2012-01-01	49.6
2012-04-01	50.3
2012-07-01	50.7
2012-10-01	50.4
2013-01-01	49.3
2013-04-01	50
2013-07-01	50.7
2013-10-01	50.6
2014-01-01	50.2
2014-04-01	51
2014-07-01	51.9
2014-10-01	51.7
2015-01-01	51.1
2015-04-01	51.6
2015-07-01	52.4
2015-10-01	52.6
2016-01-01	52.1
2016-04-01	52.7
2016-07-01	53.0
2016-10-01	53.2
2017-01-01	53.2
2017-04-01	53.9
2017-07-01	54.0
2017-10-01	53.7
2018-01-01	53.7
2018-04-01	54.4