Quarter	Percent
1999-01-01	37.3
1999-04-01	38.2
1999-07-01	38.7
1999-10-01	39.6
2000-01-01	40.3
2000-04-01	41.2
2000-07-01	41.6
2000-10-01	42.1
2001-01-01	42.6
2001-04-01	42.8
2001-07-01	43.4
2001-10-01	43.7
2002-01-01	44.2
2002-04-01	45
2002-07-01	45.3
2002-10-01	45.7
2003-01-01	45.8
2003-04-01	46.8
2003-07-01	47.3
2003-10-01	47.8
2004-01-01	47.9
2004-04-01	48.5
2004-07-01	49.2
2004-10-01	49.7
2005-01-01	50.3
2005-04-01	51.9
2005-07-01	52.3
2005-10-01	52.6
2006-01-01	52.8
2006-04-01	53.8
2006-07-01	53.9
2006-10-01	54.5
2007-01-01	54.5
2007-04-01	55.3
2007-07-01	55.5
2007-10-01	55.6
2008-01-01	55.2
2008-04-01	55.7
2008-07-01	55.6
2008-10-01	55
2009-01-01	53.3
2009-04-01	53.3
2009-07-01	53.4
2009-10-01	53
2010-01-01	52.7
2010-04-01	52.6
2010-07-01	52.9
2010-10-01	53
2011-01-01	52.3
2011-04-01	53.4
2011-07-01	52.7
2011-10-01	51.9
2012-01-01	51.4
2012-04-01	51.6
2012-07-01	51.1
2012-10-01	50.5
2013-01-01	49.9
2013-04-01	50.2
2013-07-01	50.5
2013-10-01	50.6
2014-01-01	50.4
2014-04-01	51.3
2014-07-01	51.2
2014-10-01	52
2015-01-01	51.5
2015-04-01	52.7
2015-07-01	53.0
2015-10-01	53.5
2016-01-01	53.3
2016-04-01	54.2
2016-07-01	54.8
2016-10-01	54.9
2017-01-01	54.6
2017-04-01	55.7
2017-07-01	56.1
2017-10-01	56.2
2018-01-01	55.7
2018-04-01	57.0
2018-07-01	57.3