Quarter	Percent
1999-04-01	48.8
2000-01-01	46.5
2000-04-01	52.7
2000-07-01	48.8
2000-10-01	48.1
2001-01-01	51.5
2001-04-01	48.2
2001-07-01	46.3
2001-10-01	45.8
2002-01-01	46.7
2002-04-01	44.7
2002-07-01	44.6
2002-10-01	44.3
2003-01-01	45.5
2003-04-01	44.9
2003-07-01	46.8
2003-10-01	42
2004-01-01	41.4
2004-04-01	45.7
2004-07-01	45.4
2004-10-01	42.4
2005-01-01	40.7
2005-04-01	41.2
2005-07-01	41.3
2005-10-01	41.2
2006-01-01	40.2
2006-04-01	35.4
2006-07-01	39.8
2006-10-01	40.8
2007-01-01	37
2007-04-01	35.2
2007-07-01	40.3
2007-10-01	38.9
2008-01-01	36.5
2008-04-01	36.7
2008-07-01	35.6
2008-10-01	31.2
2009-01-01	32.8
2009-04-01	34.2
2009-07-01	33.7
2009-10-01	33.2
2010-01-01	36
2010-04-01	36.7
2010-07-01	35.4
2010-10-01	34.9
2011-01-01	34
2011-04-01	36.4
2011-07-01	36.9
2011-10-01	32.3
2012-01-01	33.7
2012-04-01	34.7
2012-07-01	34.8
2012-10-01	36.4
2013-01-01	32.9
2013-04-01	30.4
2013-07-01	34.4
2013-10-01	35.7
2014-01-01	36.2
2014-04-01	32.3
2014-07-01	29.9
2014-10-01	31
2015-01-01	33.6
2015-04-01	32.8
2015-07-01	27.6
2015-10-01	31.2
2016-01-01	32.8
2016-04-01	26.0
2016-07-01	26.4
2016-10-01	31.0
2017-01-01	28.9
2017-04-01	28.1
2017-07-01	27.8
2017-10-01	26.4
2018-01-01	27.4
2018-04-01	28.4