Quarter	Percent
1999-04-01	31.7
2000-04-01	31.8
2001-04-01	32.3
2002-04-01	32.3
2003-01-01	27
2003-04-01	27
2003-07-01	27
2003-10-01	27
2004-01-01	23.3
2004-04-01	23.3
2004-07-01	23.3
2004-10-01	23.3
2005-01-01	24.9
2005-04-01	24.9
2005-07-01	24.9
2005-10-01	24.9
2006-01-01	23.3
2006-04-01	23.3
2006-07-01	23.3
2006-10-01	23.3
2007-01-01	22.6
2007-04-01	22.4
2007-07-01	22.4
2007-10-01	22.5
2008-01-01	21.9
2008-04-01	26.2
2008-07-01	22
2008-10-01	25.2
2009-01-01	20.2
2009-04-01	29.6
2009-07-01	28.1
2009-10-01	28.9
2010-01-01	19.4
2010-04-01	19.4
2010-07-01	24
2010-10-01	22
2011-01-01	23.1
2011-04-01	17.2
2011-07-01	22.3
2011-10-01	20.2
2012-01-01	19.1
2012-04-01	19.3
2012-07-01	23.9
2012-10-01	24.6
2013-01-01	18.3
2013-04-01	21
2013-07-01	21.2
2013-10-01	27.2
2014-01-01	24
2014-04-01	19.3
2014-07-01	16.6
2014-10-01	21.5
2015-01-01	28.2
2015-04-01	28.9
2015-07-01	33.6
2015-10-01	25.5
2016-01-01	22.6
2016-04-01	24.6
2016-07-01	26.6
2016-10-01	25.9
2017-01-01	25.7
2017-04-01	23.1
2017-07-01	29.2
2017-10-01	25.2
2018-01-01	27.6
2018-04-01	24.6