Quarter	Percent
1998-01-01	12.0
1998-04-01	9.5
1998-07-01	10.4
1998-10-01	10.9
1999-01-01	10.3
1999-04-01	9.2
1999-07-01	8.7
1999-10-01	8.4
2000-01-01	10.1
2000-04-01	8.3
2000-07-01	8.7
2000-10-01	8.4
2001-01-01	9.5
2001-04-01	9.0
2001-07-01	9.0
2001-10-01	10.2
2002-01-01	10.6
2002-04-01	10.5
2002-07-01	12.1
2002-10-01	13.5
2003-01-01	14.2
2003-04-01	13.5
2003-07-01	14.8
2003-10-01	15.8
2004-01-01	15.6
2004-04-01	14.1
2004-07-01	16.1
2004-10-01	16
2005-01-01	16.2
2005-04-01	15.5
2005-07-01	16.7
2005-10-01	16.5
2006-01-01	16
2006-04-01	14.9
2006-07-01	17
2006-10-01	18.2
2007-01-01	18.3
2007-04-01	15.4
2007-07-01	16.1
2007-10-01	17
2008-01-01	16.7
2008-04-01	14.4
2008-07-01	17.2
2008-10-01	18.4
2009-01-01	20.3
2009-04-01	18.9
2009-07-01	19.5
2009-10-01	22.6
2010-01-01	23.2
2010-04-01	20.7
2010-07-01	23.8
2010-10-01	23.3
2011-01-01	28
2011-04-01	27.3
2011-07-01	30.3
2011-10-01	35.3
2012-01-01	36.3
2012-04-01	35.7
2012-07-01	39.2
2012-10-01	40.5
2013-01-01	42.5
2013-04-01	37.4
2013-07-01	36.4
2013-10-01	36.1
2014-01-01	37.5
2014-04-01	35.6
2014-07-01	32.2
2014-10-01	34
2015-01-01	34.4
2015-04-01	29.8
2015-07-01	30.8
2015-10-01	32.8
2016-01-01	31.0
2016-04-01	26.9
2016-07-01	26.1
2016-10-01	27.7
2017-01-01	25.1
2017-04-01	22.7
2017-07-01	24.2
2017-10-01	23.5
2018-01-01	21.9
2018-04-01	19.4