Quarter	Percent
1999-04-01	32.3
2000-01-01	29.3
2000-04-01	27.8
2000-07-01	25.4
2000-10-01	25.8
2001-01-01	26.9
2001-04-01	26.4
2001-07-01	24.9
2001-10-01	26.6
2002-01-01	27.7
2002-04-01	26.1
2002-07-01	25
2002-10-01	26.3
2003-01-01	27.3
2003-04-01	26.4
2003-07-01	26.2
2003-10-01	28.3
2004-01-01	28.4
2004-04-01	28
2004-07-01	28.1
2004-10-01	29.2
2005-01-01	29.5
2005-04-01	28.7
2005-07-01	28
2005-10-01	29.7
2006-01-01	30.2
2006-04-01	29.6
2006-07-01	28.1
2006-10-01	29
2007-01-01	28.6
2007-04-01	27
2007-07-01	25.5
2007-10-01	27.9
2008-01-01	27.9
2008-04-01	26.6
2008-07-01	25.8
2008-10-01	27
2009-01-01	27.1
2009-04-01	27
2009-07-01	26.4
2009-10-01	28.3
2010-01-01	31.4
2010-04-01	30.7
2010-07-01	29.9
2010-10-01	31.9
2011-01-01	33.5
2011-04-01	32.6
2011-07-01	30.5
2011-10-01	31.0
2012-01-01	31.6
2012-04-01	31.1
2012-07-01	29.6
2012-10-01	30.8
2013-01-01	31.6
2013-04-01	30.7
2013-07-01	29.7
2013-10-01	31.2
2014-01-01	33.2
2014-04-01	33.0
2014-07-01	31.7
2014-10-01	32.6
2015-01-01	32.5
2015-04-01	31.1
2015-07-01	30.3
2015-10-01	32.2
2016-01-01	32.8
2016-04-01	31.4
2016-07-01	30.6
2016-10-01	32.4
2017-01-01	33.0
2017-04-01	31.9
2017-07-01	30.1
2017-10-01	31.6
2018-01-01	32.3
2018-04-01	31.3