Quarter	Percent
1999-04-01	22.8
2000-01-01	25.4
2000-04-01	26.4
2000-07-01	27
2000-10-01	27.9
2001-01-01	28.2
2001-04-01	28.3
2001-07-01	28.5
2001-10-01	28.7
2002-01-01	29.7
2002-04-01	29.4
2002-07-01	31.6
2002-10-01	31.7
2003-01-01	32.4
2003-04-01	32.6
2003-07-01	32.8
2003-10-01	32.5
2004-01-01	33.6
2004-04-01	33.6
2004-07-01	34.9
2004-10-01	35.5
2005-01-01	36
2005-04-01	36.3
2005-07-01	36.5
2005-10-01	37.1
2006-01-01	37.5
2006-04-01	38
2006-07-01	39
2006-10-01	39.7
2007-01-01	40.1
2007-04-01	41.5
2007-07-01	42
2007-10-01	42
2008-01-01	42.5
2008-04-01	43.4
2008-07-01	43.8
2008-10-01	44.3
2009-01-01	45.9
2009-04-01	45.2
2009-07-01	46.3
2009-10-01	46.6
2010-01-01	43.8
2010-04-01	43.9
2010-07-01	44.5
2010-10-01	45.7
2011-01-01	46.9
2011-04-01	47.5
2011-07-01	48.5
2011-10-01	50
2012-01-01	49.9
2012-04-01	50.8
2012-07-01	51.0
2012-10-01	52.2
2013-01-01	52.2
2013-04-01	52.7
2013-07-01	53.0
2013-10-01	53.2
2014-01-01	53.5
2014-04-01	54
2014-07-01	54.9
2014-10-01	54.9
2015-01-01	55.5
2015-04-01	56.9
2015-07-01	57.2
2015-10-01	57.1
2016-01-01	57.9
2016-04-01	58.7
2016-07-01	59.0
2016-10-01	58.7
2017-01-01	59.3
2017-04-01	60.4
2017-07-01	60.2
2017-10-01	60.6
2018-01-01	60.9
2018-04-01	61.8