Quarter	Percent
1999-04-01	35.3
2000-01-01	36.6
2000-04-01	37.9
2000-07-01	38.8
2000-10-01	39.4
2001-01-01	39.4
2001-04-01	39.3
2001-07-01	39.4
2001-10-01	40.3
2002-01-01	40.9
2002-04-01	42
2002-07-01	43.3
2002-10-01	43.2
2003-01-01	44.2
2003-04-01	44.5
2003-07-01	44.4
2003-10-01	44.2
2004-01-01	44.8
2004-04-01	44.6
2004-07-01	45.6
2004-10-01	46
2005-01-01	45.8
2005-04-01	46.2
2005-07-01	46.3
2005-10-01	46.2
2006-01-01	46.1
2006-04-01	47.4
2006-07-01	48.2
2006-10-01	48.9
2007-01-01	49.6
2007-04-01	51
2007-07-01	51.4
2007-10-01	51.4
2008-01-01	51.7
2008-04-01	52.7
2008-07-01	53.5
2008-10-01	54
2009-01-01	54.9
2009-04-01	54.8
2009-07-01	55.5
2009-10-01	55.2
2010-01-01	52.9
2010-04-01	53.6
2010-07-01	53.9
2010-10-01	54.4
2011-01-01	53.9
2011-04-01	54.7
2011-07-01	55.6
2011-10-01	56.5
2012-01-01	56.6
2012-04-01	57.5
2012-07-01	57.9
2012-10-01	58.4
2013-01-01	58.3
2013-04-01	58.9
2013-07-01	59.6
2013-10-01	59.9
2014-01-01	59.0
2014-04-01	59.6
2014-07-01	60.2
2014-10-01	60.6
2015-01-01	61.1
2015-04-01	61.7
2015-07-01	61.9
2015-10-01	62.2
2016-01-01	62.7
2016-04-01	63.2
2016-07-01	63.8
2016-10-01	64.2
2017-01-01	64.6
2017-04-01	65.5
2017-07-01	66.0
2017-10-01	66.5
2018-01-01	66.5
2018-04-01	67.3