Quarter	Percent
1999-04-01	45.7
1999-07-01	35.4
1999-10-01	43.6
2000-01-01	45
2000-04-01	44
2000-07-01	34.8
2000-10-01	43.6
2001-01-01	44.6
2001-04-01	45.3
2001-07-01	35.8
2001-10-01	45
2002-01-01	46.2
2002-04-01	47.2
2002-07-01	38.6
2002-10-01	45.1
2003-01-01	46
2003-04-01	46.8
2003-07-01	38.3
2003-10-01	44.8
2004-01-01	46.2
2004-04-01	47.1
2004-07-01	38
2004-10-01	45.1
2005-01-01	46.2
2005-04-01	46.6
2005-07-01	37.3
2005-10-01	43.5
2006-01-01	43.9
2006-04-01	42.8
2006-07-01	34.5
2006-10-01	41.7
2007-01-01	26.5
2007-04-01	25.6
2007-07-01	22.1
2007-10-01	27.9
2008-01-01	30.6
2008-04-01	28.9
2008-07-01	25.6
2008-10-01	34.8
2009-01-01	38.3
2009-04-01	34.9
2009-07-01	35.6
2009-10-01	40.2
2010-01-01	44.9
2010-04-01	42.4
2010-07-01	41.8
2010-10-01	46.9
2011-01-01	49.0
2011-04-01	46.5
2011-07-01	44.0
2011-10-01	46.2
2012-01-01	51.6
2012-04-01	46.9
2012-07-01	44.2
2012-10-01	49.7
2013-01-01	52.2
2013-04-01	47.4
2013-07-01	44.4
2013-10-01	49.5
2014-01-01	52.4
2014-04-01	49.9
2014-07-01	46.6
2014-10-01	50.4
2015-01-01	51.5
2015-04-01	49.7
2015-07-01	46.4
2015-10-01	51.8
2016-01-01	52.6
2016-04-01	45.5
2016-07-01	41.5
2016-10-01	49.7
2017-01-01	54.3
2017-04-01	50.3
2017-07-01	51.3
2017-10-01	52.6
2018-01-01	55.2
2018-04-01	51.2