Quarter	Percent
1999-04-01	17.5
2000-04-01	16.8
2001-04-01	14.4
2002-04-01	18.1
2003-01-01	20.6
2003-04-01	20.6
2003-07-01	20.6
2003-10-01	20.6
2004-01-01	22.2
2004-04-01	22.2
2004-07-01	22.2
2004-10-01	22.2
2005-01-01	24.9
2005-04-01	24.9
2005-07-01	24.9
2005-10-01	24.9
2006-01-01	27.8
2006-04-01	27.8
2006-07-01	27.8
2006-10-01	27.8
2007-01-01	28.1
2007-04-01	27.4
2007-07-01	31.6
2007-10-01	27.3
2008-01-01	30
2008-04-01	32.1
2008-07-01	29.8
2008-10-01	25.3
2009-01-01	25.4
2009-04-01	31
2009-07-01	30
2009-10-01	31.1
2010-01-01	29.1
2010-04-01	34
2010-07-01	29.8
2010-10-01	32.1
2011-01-01	30.9
2011-04-01	31.8
2011-07-01	34.8
2011-10-01	27.8
2012-01-01	33.3
2012-04-01	35.3
2012-07-01	37.2
2012-10-01	31.5
2013-01-01	28.6
2013-04-01	39.7
2013-07-01	32.2
2013-10-01	29.1
2014-01-01	36.5
2014-04-01	34.5
2014-07-01	35.1
2014-10-01	34
2015-01-01	37.0
2015-04-01	33.6
2015-07-01	30.2
2015-10-01	34.0
2016-01-01	33.6
2016-04-01	30.3
2016-07-01	31.8
2016-10-01	34.1
2017-01-01	31.9
2017-04-01	31.8
2017-07-01	35.6
2017-10-01	36.1
2018-01-01	34.3
2018-04-01	35.1