Quarter	Percent
1999-04-01	49.4
1999-07-01	38.4
1999-10-01	47.1
2000-01-01	48.8
2000-04-01	48.6
2000-07-01	38.6
2000-10-01	47.3
2001-01-01	48.8
2001-04-01	50.1
2001-07-01	39.9
2001-10-01	48.6
2002-01-01	49.7
2002-04-01	51.3
2002-07-01	42.2
2002-10-01	48.9
2003-01-01	50.1
2003-04-01	50.6
2003-07-01	41.8
2003-10-01	48.3
2004-01-01	49.8
2004-04-01	51.1
2004-07-01	41.8
2004-10-01	47.6
2005-01-01	49.4
2005-04-01	49.5
2005-07-01	41
2005-10-01	47
2006-01-01	48.1
2006-04-01	47.3
2006-07-01	38.9
2006-10-01	45.9
2007-01-01	32.6
2007-04-01	30.6
2007-07-01	26.9
2007-10-01	32.5
2008-01-01	35.1
2008-04-01	33.1
2008-07-01	29.8
2008-10-01	38.2
2009-01-01	40.7
2009-04-01	37.8
2009-07-01	38.4
2009-10-01	42.9
2010-01-01	48.0
2010-04-01	45.0
2010-07-01	44.1
2010-10-01	47.4
2011-01-01	50.3
2011-04-01	48.1
2011-07-01	47.0
2011-10-01	49.1
2012-01-01	52.4
2012-04-01	48.4
2012-07-01	46.5
2012-10-01	51.5
2013-01-01	53.6
2013-04-01	48.6
2013-07-01	46.4
2013-10-01	51.8
2014-01-01	54.8
2014-04-01	52.4
2014-07-01	48.2
2014-10-01	52.5
2015-01-01	54.7
2015-04-01	52.8
2015-07-01	49.0
2015-10-01	53.7
2016-01-01	55.3
2016-04-01	47.2
2016-07-01	44.6
2016-10-01	50.6
2017-01-01	54.5
2017-04-01	51.1
2017-07-01	53.0
2017-10-01	54.5
2018-01-01	57.2
2018-04-01	52.7