Quarter	Percent
1999-01-01	23.2
1999-04-01	23.8
1999-07-01	25.4
1999-10-01	26.1
2000-01-01	25.6
2000-04-01	26.8
2000-07-01	27.6
2000-10-01	26.6
2001-01-01	26.7
2001-04-01	27.4
2001-07-01	28.5
2001-10-01	27.6
2002-01-01	27.8
2002-04-01	27.8
2002-07-01	29.5
2002-10-01	28.5
2003-01-01	27.9
2003-04-01	28.8
2003-07-01	30.2
2003-10-01	28.6
2004-01-01	28.6
2004-04-01	29.3
2004-07-01	30.7
2004-10-01	29.3
2005-01-01	30.4
2005-04-01	33
2005-07-01	35.2
2005-10-01	33.3
2006-01-01	33.8
2006-04-01	34.8
2006-07-01	35.8
2006-10-01	33.6
2007-01-01	32.3
2007-04-01	33.6
2007-07-01	36.5
2007-10-01	33.6
2008-01-01	32.1
2008-04-01	32.7
2008-07-01	34.5
2008-10-01	31.1
2009-01-01	27.3
2009-04-01	26.7
2009-07-01	27.3
2009-10-01	25.3
2010-01-01	24.6
2010-04-01	23.8
2010-07-01	25.5
2010-10-01	23.2
2011-01-01	22
2011-04-01	22.3
2011-07-01	23.2
2011-10-01	20.4
2012-01-01	19
2012-04-01	18.4
2012-07-01	19
2012-10-01	16.7
2013-01-01	16.4
2013-04-01	15.7
2013-07-01	17.1
2013-10-01	16
2014-01-01	15.2
2014-04-01	15.8
2014-07-01	16.6
2014-10-01	16.3
2015-01-01	16.1
2015-04-01	17.4
2015-07-01	19.0
2015-10-01	16.6
2016-01-01	16.0
2016-04-01	16.6
2016-07-01	19.3
2016-10-01	17.1
2017-01-01	17.6
2017-04-01	19.2
2017-07-01	22.0
2017-10-01	20.0
2018-01-01	19.1
2018-04-01	20.4
2018-07-01	22.2