Quarter	Percent
1999-04-01	26.9
1999-07-01	27.2
1999-10-01	27.4
2000-01-01	27.4
2000-04-01	27.7
2000-07-01	27.8
2000-10-01	28.4
2001-01-01	29.2
2001-04-01	29.2
2001-07-01	29.6
2001-10-01	29.7
2002-01-01	30.5
2002-04-01	31.4
2002-07-01	31.8
2002-10-01	32.5
2003-01-01	32.9
2003-04-01	34.1
2003-07-01	34.3
2003-10-01	34
2004-01-01	34.2
2004-04-01	34.6
2004-07-01	33.6
2004-10-01	35.4
2005-01-01	36.8
2005-04-01	38.4
2005-07-01	38.2
2005-10-01	39.4
2006-01-01	39.8
2006-04-01	40.8
2006-07-01	39.9
2006-10-01	39.5
2007-01-01	40.6
2007-04-01	41.2
2007-07-01	40.6
2007-10-01	41.7
2008-01-01	41.7
2008-04-01	42.8
2008-07-01	43.6
2008-10-01	42.7
2009-01-01	43.8
2009-04-01	43.7
2009-07-01	44.5
2009-10-01	43.7
2010-01-01	44.9
2010-04-01	46.7
2010-07-01	46.8
2010-10-01	45.1
2011-01-01	46.2
2011-04-01	47.3
2011-07-01	47.2
2011-10-01	47.1
2012-01-01	46.6
2012-04-01	46.9
2012-07-01	46.7
2012-10-01	47.1
2013-01-01	48.0
2013-04-01	48.4
2013-07-01	48.0
2013-10-01	49.0
2014-01-01	48.8
2014-04-01	49.3
2014-07-01	49.2
2014-10-01	49.6
2015-01-01	49.4
2015-04-01	50.1
2015-07-01	50.1
2015-10-01	50.7
2016-01-01	52.3
2016-04-01	51.8
2016-07-01	51.2
2016-10-01	52.4
2017-01-01	53.5
2017-04-01	54.0
2017-07-01	52.5
2017-10-01	54.6
2018-01-01	53.5
2018-04-01	54.2