Quarter	Percent
1998-04-01	29.2
1999-04-01	31.5
2000-04-01	29.4
2001-04-01	31.4
2002-04-01	29.6
2003-04-01	29.6
2004-04-01	31.9
2005-04-01	33.4
2006-04-01	29.8
2007-04-01	29.8
2008-04-01	31.9
2009-04-01	33.9
2010-01-01	32.4
2010-04-01	31.8
2010-07-01	28.9
2010-10-01	31.6
2011-01-01	31.7
2011-04-01	33.1
2011-07-01	29.3
2011-10-01	29.2
2012-01-01	33.0
2012-04-01	34.0
2012-07-01	28.3
2012-10-01	29.1
2013-01-01	29.9
2013-04-01	32.6
2013-07-01	31.1
2013-10-01	30.8
2014-01-01	32.3
2014-04-01	32.9
2014-07-01	29.6
2014-10-01	31.8
2015-01-01	34.9
2015-04-01	34.6
2015-07-01	31.5
2015-10-01	31.9
2016-01-01	32.0
2016-04-01	35.7
2016-07-01	31.8
2016-10-01	29.4
2017-01-01	31.8
2017-04-01	32.4
2017-07-01	27.3
2017-10-01	30.4
2018-01-01	33.2
2018-04-01	33.1