Quarter	Percent
1999-01-01	30.1
1999-04-01	31.2
1999-07-01	34.9
1999-10-01	32.7
2000-01-01	27.3
2000-04-01	27.4
2000-07-01	34.7
2000-10-01	29.4
2001-01-01	27.6
2001-04-01	26.4
2001-07-01	28.7
2001-10-01	24.4
2002-01-01	25.8
2002-04-01	27.2
2002-07-01	27.6
2002-10-01	25.4
2003-01-01	23.4
2003-04-01	23.6
2003-07-01	24.6
2003-10-01	25.6
2004-01-01	26
2004-04-01	29.1
2004-07-01	31.6
2004-10-01	27.6
2005-01-01	27.6
2005-04-01	26.8
2005-07-01	33.9
2005-10-01	31
2006-01-01	27.5
2006-04-01	31.8
2006-07-01	32.4
2006-10-01	29.5
2007-01-01	28.2
2007-04-01	31.1
2007-07-01	36.9
2007-10-01	29.8
2008-01-01	29.8
2008-04-01	31.4
2008-07-01	39.6
2008-10-01	32
2009-01-01	27
2009-04-01	30.3
2009-07-01	37.9
2009-10-01	28.7
2010-01-01	29.9
2010-04-01	30.3
2010-07-01	31.5
2010-10-01	28.3
2011-01-01	23.5
2011-04-01	26.2
2011-07-01	28.6
2011-10-01	29.2
2012-01-01	25.9
2012-04-01	20.2
2012-07-01	25.7
2012-10-01	23.1
2013-01-01	21.7
2013-04-01	21.2
2013-07-01	28.5
2013-10-01	20.8
2014-01-01	20.1
2014-04-01	24.1
2014-07-01	27.1
2014-10-01	24.6
2015-01-01	22.1
2015-04-01	29.5
2015-07-01	30.7
2015-10-01	26.0
2016-01-01	22.9
2016-04-01	26.2
2016-07-01	29.3
2016-10-01	25.8
2017-01-01	28.4
2017-04-01	29.7
2017-07-01	33.3
2017-10-01	30.2
2018-01-01	30.6
2018-04-01	31.9