Quarter	Percent
1999-04-01	49.8
2000-04-01	48.3
2001-04-01	48
2002-04-01	46.5
2003-01-01	46.5
2003-04-01	46.5
2003-07-01	46.5
2003-10-01	46.5
2004-01-01	44.2
2004-04-01	44.2
2004-07-01	44.2
2004-10-01	44.2
2005-01-01	43
2005-04-01	43
2005-07-01	43
2005-10-01	43
2006-01-01	41.8
2006-04-01	41.8
2006-07-01	41.8
2006-10-01	41.8
2007-01-01	41.1
2007-04-01	43.5
2007-07-01	40.6
2007-10-01	39.3
2008-01-01	41.6
2008-04-01	40.6
2008-07-01	41.3
2008-10-01	41.6
2009-01-01	38.8
2009-04-01	39.6
2009-07-01	39.3
2009-10-01	39.5
2010-01-01	39.6
2010-04-01	40.7
2010-07-01	39.2
2010-10-01	39.3
2011-01-01	37.7
2011-04-01	39.9
2011-07-01	39.4
2011-10-01	40.1
2012-01-01	38.5
2012-04-01	38.5
2012-07-01	35.2
2012-10-01	36.9
2013-01-01	37.3
2013-04-01	35.8
2013-07-01	37.8
2013-10-01	36.4
2014-01-01	35.9
2014-04-01	36.2
2014-07-01	36.1
2014-10-01	35
2015-01-01	33.4
2015-04-01	34.1
2015-07-01	34.8
2015-10-01	35.2
2016-01-01	35.8
2016-04-01	36.2
2016-07-01	34.7
2016-10-01	34.5
2017-01-01	34.2
2017-04-01	34.7
2017-07-01	32.2
2017-10-01	34.3
2018-01-01	32.3
2018-04-01	33.7