Quarter	Percent
1999-01-01	27.2
2000-01-01	24.4
2000-04-01	26.4
2000-07-01	29.3
2000-10-01	28.7
2001-01-01	28
2001-04-01	26.6
2001-07-01	26.8
2001-10-01	25
2002-01-01	24.1
2002-04-01	24.4
2002-07-01	25.3
2002-10-01	22.8
2003-01-01	22.1
2003-04-01	24.1
2003-07-01	25
2003-10-01	24.6
2004-01-01	23.6
2004-04-01	23.8
2004-07-01	25.6
2004-10-01	26.1
2005-01-01	24.6
2005-04-01	23.9
2005-07-01	26.9
2005-10-01	26.2
2006-01-01	24.3
2006-04-01	25.9
2006-07-01	29.1
2006-10-01	28.5
2007-01-01	27.4
2007-04-01	28.9
2007-07-01	30.6
2007-10-01	30.1
2008-01-01	29.7
2008-04-01	30.1
2008-07-01	32.2
2008-10-01	31.7
2009-01-01	30.2
2009-04-01	30
2009-07-01	30.8
2009-10-01	30.4
2010-01-01	29.6
2010-04-01	30.3
2010-07-01	31.7
2010-10-01	30.4
2011-01-01	28
2011-04-01	29.6
2011-07-01	31.2
2011-10-01	29.4
2012-01-01	28.1
2012-04-01	29.1
2012-07-01	30.1
2012-10-01	29.7
2013-01-01	27.8
2013-04-01	28.7
2013-07-01	29.4
2013-10-01	28.6
2014-01-01	28.7
2014-04-01	29.9
2014-07-01	30.9
2014-10-01	30.4
2015-01-01	29.2
2015-04-01	30.3
2015-07-01	31.5
2015-10-01	30.8
2016-01-01	31.9
2016-04-01	33.1
2016-07-01	33.5
2016-10-01	32.9
2017-01-01	33.2
2017-04-01	33.9
2017-07-01	34.5
2017-10-01	34.0
2018-01-01	35.5
2018-04-01	34.5