Quarter	Percent
1998-01-01	34.2
1998-04-01	33.8
1998-07-01	32.2
1998-10-01	35.2
1999-01-01	34.5
1999-04-01	32.9
1999-07-01	30.7
1999-10-01	33.3
2000-01-01	32.3
2000-04-01	31.5
2000-07-01	30.3
2000-10-01	30.5
2001-01-01	29.2
2001-04-01	27.8
2001-07-01	27.4
2001-10-01	28.4
2002-01-01	28.1
2002-04-01	27.1
2002-07-01	26.1
2002-10-01	27.6
2003-01-01	28.2
2003-04-01	26.8
2003-07-01	25.8
2003-10-01	27.5
2004-01-01	23.4
2004-04-01	24.4
2004-07-01	21.4
2004-10-01	24.8
2005-01-01	25.3
2005-04-01	22.8
2005-07-01	23.7
2005-10-01	24.6
2006-01-01	24.2
2006-04-01	20.8
2006-07-01	19.1
2006-10-01	22.9
2007-01-01	20.8
2007-04-01	18.5
2007-07-01	18.9
2007-10-01	23.3
2008-01-01	21.1
2008-04-01	20.4
2008-07-01	19.6
2008-10-01	23.8
2009-01-01	26.1
2009-04-01	23.8
2009-07-01	23.4
2009-10-01	28
2010-01-01	28.9
2010-04-01	28
2010-07-01	24.8
2010-10-01	29.8
2011-01-01	29.8
2011-04-01	27.6
2011-07-01	26.4
2011-10-01	32.5
2012-01-01	35.7
2012-04-01	34.3
2012-07-01	32.2
2012-10-01	39
2013-01-01	41.9
2013-04-01	37.3
2013-07-01	37.3
2013-10-01	43.5
2014-01-01	46.2
2014-04-01	41.6
2014-07-01	39.6
2014-10-01	43.3
2015-01-01	44.9
2015-04-01	41.1
2015-07-01	35.3
2015-10-01	40.0
2016-01-01	40.3
2016-04-01	35.5
2016-07-01	34.5
2016-10-01	40.7
2017-01-01	37.3
2017-04-01	34.2
2017-07-01	32.3
2017-10-01	35.2
2018-01-01	33.8
2018-04-01	31.6