Quarter	Percent
1999-01-01	31.6
2000-01-01	39.6
2000-04-01	37.2
2000-07-01	35.8
2000-10-01	36.5
2001-01-01	39.9
2001-04-01	40.6
2001-07-01	41.7
2001-10-01	41.9
2002-01-01	43
2002-04-01	42.4
2002-07-01	44.8
2002-10-01	43
2003-01-01	43.2
2003-04-01	42.8
2003-07-01	43.4
2003-10-01	43
2004-01-01	45.2
2004-04-01	41.5
2004-07-01	40.1
2004-10-01	41
2005-01-01	42.2
2005-04-01	39.5
2005-07-01	35.8
2005-10-01	35.9
2006-01-01	35
2006-04-01	30.4
2006-07-01	30.3
2006-10-01	30.9
2007-01-01	27.5
2007-04-01	22.8
2007-07-01	23.8
2007-10-01	20.9
2008-01-01	21
2008-04-01	19.5
2008-07-01	19.1
2008-10-01	19.8
2009-01-01	20
2009-04-01	19.9
2009-07-01	22.9
2009-10-01	22.1
2010-01-01	24.9
2010-04-01	25
2010-07-01	25.8
2010-10-01	26.1
2011-01-01	28.2
2011-04-01	26.4
2011-07-01	30.3
2011-10-01	30.3
2012-01-01	30.5
2012-04-01	28.1
2012-07-01	29.7
2012-10-01	31.5
2013-01-01	32.7
2013-04-01	28.5
2013-07-01	29.5
2013-10-01	29.6
2014-01-01	28.7
2014-04-01	24.1
2014-07-01	25.5
2014-10-01	23.6
2015-01-01	23.3
2015-04-01	18.9
2015-07-01	20.8
2015-10-01	20.6
2016-01-01	20.5
2016-04-01	16.6
2016-07-01	18.5
2016-10-01	16.2
2017-01-01	16.0
2017-04-01	13.5
2017-07-01	15.6
2017-10-01	15.4
2018-01-01	12.5
2018-04-01	9.2