Quarter	Percent
1999-04-01	40.5
2000-01-01	41.7
2000-04-01	40.3
2000-07-01	40.8
2000-10-01	39.6
2001-01-01	38.7
2001-04-01	38.6
2001-07-01	38.2
2001-10-01	37.9
2002-01-01	38.5
2002-04-01	36
2002-07-01	37.4
2002-10-01	38.1
2003-01-01	36.5
2003-04-01	37.6
2003-07-01	37.2
2003-10-01	36.8
2004-01-01	38.9
2004-04-01	38.3
2004-07-01	39.2
2004-10-01	38.9
2005-01-01	39
2005-04-01	40.1
2005-07-01	38.4
2005-10-01	39
2006-01-01	38.7
2006-04-01	38.1
2006-07-01	37.6
2006-10-01	37
2007-01-01	36.8
2007-04-01	35.3
2007-07-01	35.3
2007-10-01	34.6
2008-01-01	35.4
2008-04-01	35.1
2008-07-01	35.5
2008-10-01	35.1
2009-01-01	35.5
2009-04-01	35
2009-07-01	35
2009-10-01	34.5
2010-01-01	35.1
2010-04-01	33.5
2010-07-01	35.2
2010-10-01	34
2011-01-01	34.3
2011-04-01	32.5
2011-07-01	33
2011-10-01	32.8
2012-01-01	32.8
2012-04-01	32.4
2012-07-01	32.2
2012-10-01	32.6
2013-01-01	33.3
2013-04-01	31.6
2013-07-01	31.7
2013-10-01	31.8
2014-01-01	31.8
2014-04-01	31.5
2014-07-01	30.3
2014-10-01	29.6
2015-01-01	30.9
2015-04-01	29.9
2015-07-01	29.8
2015-10-01	30.2
2016-01-01	30.1
2016-04-01	29.6
2016-07-01	29.5
2016-10-01	29.5
2017-01-01	30.1
2017-04-01	30.6
2017-07-01	30.7
2017-10-01	31.1
2018-01-01	31.7
2018-04-01	30.7