Quarter	Percent
1999-01-01	28.4
1999-04-01	26.7
1999-07-01	25.4
1999-10-01	30.2
2000-01-01	29.9
2000-04-01	28.1
2000-07-01	28.5
2000-10-01	30.6
2001-01-01	32.1
2001-04-01	32.8
2001-07-01	28.3
2001-10-01	34.7
2002-01-01	33.4
2002-04-01	31.2
2002-07-01	29.2
2002-10-01	31.9
2003-01-01	36.3
2003-04-01	34.1
2003-07-01	30.7
2003-10-01	36.4
2004-01-01	32.4
2004-04-01	33.6
2004-07-01	28.4
2004-10-01	34.1
2005-01-01	32.4
2005-04-01	32.8
2005-07-01	30.5
2005-10-01	31.8
2006-01-01	32
2006-04-01	31
2006-07-01	26.8
2006-10-01	30.4
2007-01-01	28.6
2007-04-01	27.6
2007-07-01	28.9
2007-10-01	32.4
2008-01-01	31.9
2008-04-01	26.5
2008-07-01	25.9
2008-10-01	27.1
2009-01-01	28.2
2009-04-01	27.5
2009-07-01	28
2009-10-01	32.7
2010-01-01	32.9
2010-04-01	30.4
2010-07-01	31.9
2010-10-01	34.7
2011-01-01	33
2011-04-01	31.8
2011-07-01	31.3
2011-10-01	35.6
2012-01-01	36.4
2012-04-01	34
2012-07-01	35
2012-10-01	38.4
2013-01-01	38.2
2013-04-01	38
2013-07-01	36.5
2013-10-01	40.4
2014-01-01	40.5
2014-04-01	40.2
2014-07-01	36
2014-10-01	37.3
2015-01-01	39.0
2015-04-01	38.1
2015-07-01	36.3
2015-10-01	38.2
2016-01-01	35.1
2016-04-01	33.2
2016-07-01	32.0
2016-10-01	35.2
2017-01-01	37.2
2017-04-01	36.9
2017-07-01	34.7
2017-10-01	38.2
2018-01-01	38.0
2018-04-01	35.9