Quarter	Percent
1999-01-01	29.6
2000-01-01	37.9
2000-04-01	35.7
2000-07-01	33.3
2000-10-01	34.1
2001-01-01	38.4
2001-04-01	39.2
2001-07-01	39.6
2001-10-01	40.9
2002-01-01	42.8
2002-04-01	41.6
2002-07-01	42.3
2002-10-01	43.4
2003-01-01	43.9
2003-04-01	41.4
2003-07-01	41.4
2003-10-01	40.8
2004-01-01	43
2004-04-01	40.1
2004-07-01	37.9
2004-10-01	37.1
2005-01-01	39.4
2005-04-01	38.6
2005-07-01	35.2
2005-10-01	34.4
2006-01-01	34.3
2006-04-01	30
2006-07-01	27.9
2006-10-01	27
2007-01-01	25.6
2007-04-01	21.6
2007-07-01	20.7
2007-10-01	18.7
2008-01-01	18.9
2008-04-01	17.1
2008-07-01	16.1
2008-10-01	17.1
2009-01-01	19.3
2009-04-01	19.2
2009-07-01	21.8
2009-10-01	22.3
2010-01-01	24.6
2010-04-01	23.1
2010-07-01	23.5
2010-10-01	23.5
2011-01-01	26.7
2011-04-01	24.6
2011-07-01	25.4
2011-10-01	26.4
2012-01-01	27.7
2012-04-01	25.1
2012-07-01	25.8
2012-10-01	27.4
2013-01-01	29.2
2013-04-01	26
2013-07-01	26.6
2013-10-01	27.3
2014-01-01	27.2
2014-04-01	23.1
2014-07-01	23.1
2014-10-01	22
2015-01-01	23.3
2015-04-01	19.8
2015-07-01	19.7
2015-10-01	20.2
2016-01-01	19.6
2016-04-01	16.9
2016-07-01	18.0
2016-10-01	16.0
2017-01-01	15.2
2017-04-01	14.6
2017-07-01	14.7
2017-10-01	14.7
2018-01-01	11.8
2018-04-01	10.2