Quarter	Percent
1999-01-01	42.2
1999-04-01	42.4
1999-07-01	42.8
1999-10-01	42.9
2000-01-01	42.8
2000-04-01	42.9
2000-07-01	43.3
2000-10-01	43.7
2001-01-01	43.1
2001-04-01	43
2001-07-01	43.3
2001-10-01	43.1
2002-01-01	43
2002-04-01	43.2
2002-07-01	43.3
2002-10-01	43.6
2003-01-01	43.7
2003-04-01	44.2
2003-07-01	44.6
2003-10-01	44.7
2004-01-01	44.2
2004-04-01	44
2004-07-01	44.1
2004-10-01	44.3
2005-01-01	44
2005-04-01	44.1
2005-07-01	44.4
2005-10-01	44.3
2006-01-01	44.3
2006-04-01	44.4
2006-07-01	44.4
2006-10-01	44.5
2007-01-01	44.1
2007-04-01	44.1
2007-07-01	44.2
2007-10-01	44
2008-01-01	43.3
2008-04-01	43.5
2008-07-01	44.1
2008-10-01	44.1
2009-01-01	42.9
2009-04-01	43.1
2009-07-01	43
2009-10-01	43.2
2010-01-01	43.2
2010-04-01	43.6
2010-07-01	43.9
2010-10-01	43.7
2011-01-01	43.1
2011-04-01	43.6
2011-07-01	43.9
2011-10-01	44.1
2012-01-01	43.8
2012-04-01	44.9
2012-07-01	45.7
2012-10-01	45.2
2013-01-01	44.5
2013-04-01	45.2
2013-07-01	45.6
2013-10-01	46.2
2014-01-01	47.2
2014-04-01	47.6
2014-07-01	48.4
2014-10-01	48.7
2015-01-01	48.6
2015-04-01	49.3
2015-07-01	50.0
2015-10-01	49.9
2016-01-01	50.2
2016-04-01	51.2
2016-07-01	51.8
2016-10-01	52.2
2017-01-01	51.5
2017-04-01	52.0
2017-07-01	52.4
2017-10-01	52.4
2018-01-01	52.4
2018-04-01	53.0