Quarter	Percent
1999-04-01	35.6
2000-04-01	38.6
2001-04-01	35.5
2002-04-01	37.7
2003-01-01	40.1
2003-04-01	40.1
2003-07-01	40.1
2003-10-01	40.1
2004-01-01	38.8
2004-04-01	38.8
2004-07-01	38.8
2004-10-01	38.8
2005-01-01	39.4
2005-04-01	39.4
2005-07-01	39.4
2005-10-01	39.4
2006-01-01	38.9
2006-04-01	38.9
2006-07-01	38.9
2006-10-01	38.9
2007-01-01	33.7
2007-04-01	39.7
2007-07-01	38.6
2007-10-01	33.4
2008-01-01	32.9
2008-04-01	44.5
2008-07-01	43.3
2008-10-01	37.8
2009-01-01	48.7
2009-04-01	54.1
2009-07-01	45.5
2009-10-01	42.5
2010-01-01	47.9
2010-04-01	51.6
2010-07-01	47.8
2010-10-01	47.9
2011-01-01	49.1
2011-04-01	45.2
2011-07-01	51
2011-10-01	48.4
2012-01-01	50.5
2012-04-01	44.9
2012-07-01	47.6
2012-10-01	50.3
2013-01-01	52.8
2013-04-01	51.3
2013-07-01	49.2
2013-10-01	48.5
2014-01-01	47.9
2014-04-01	54.7
2014-07-01	51.4
2014-10-01	54.3
2015-01-01	49.4
2015-04-01	48.8
2015-07-01	40.8
2015-10-01	42.8
2016-01-01	49.5
2016-04-01	50.7
2016-07-01	47.2
2016-10-01	49.0
2017-01-01	50.3
2017-04-01	48.0
2017-07-01	44.7
2017-10-01	44.5
2018-01-01	46.3
2018-04-01	45.8