Quarter	Percent
1999-01-01	27.9
2000-01-01	36.4
2000-04-01	34.3
2000-07-01	31.2
2000-10-01	32
2001-01-01	37.2
2001-04-01	38
2001-07-01	37.8
2001-10-01	40.1
2002-01-01	42.6
2002-04-01	41
2002-07-01	40.2
2002-10-01	43.8
2003-01-01	44.4
2003-04-01	40.3
2003-07-01	39.9
2003-10-01	39
2004-01-01	41.4
2004-04-01	38.9
2004-07-01	36.1
2004-10-01	34.1
2005-01-01	37.2
2005-04-01	37.9
2005-07-01	34.6
2005-10-01	33.2
2006-01-01	33.8
2006-04-01	29.7
2006-07-01	26
2006-10-01	23.9
2007-01-01	24.1
2007-04-01	20.7
2007-07-01	18.1
2007-10-01	16.9
2008-01-01	17.2
2008-04-01	15.1
2008-07-01	13.8
2008-10-01	14.9
2009-01-01	18.7
2009-04-01	18.6
2009-07-01	20.9
2009-10-01	22.5
2010-01-01	24.4
2010-04-01	21.7
2010-07-01	21.8
2010-10-01	21.8
2011-01-01	25.7
2011-04-01	23.3
2011-07-01	21.9
2011-10-01	23.7
2012-01-01	25.6
2012-04-01	23
2012-07-01	23.1
2012-10-01	24.6
2013-01-01	26.9
2013-04-01	24.3
2013-07-01	24.6
2013-10-01	25.8
2014-01-01	26.3
2014-04-01	22.3
2014-07-01	21.3
2014-10-01	20.8
2015-01-01	23.3
2015-04-01	20.4
2015-07-01	19.0
2015-10-01	20.0
2016-01-01	19.0
2016-04-01	17.2
2016-07-01	17.8
2016-10-01	15.8
2017-01-01	14.6
2017-04-01	15.4
2017-07-01	14.1
2017-10-01	14.3
2018-01-01	11.3
2018-04-01	11.0