Quarter	Percent
1999-04-01	26.3
2000-04-01	27.2
2001-04-01	24.8
2002-04-01	27.9
2003-01-01	30.3
2003-04-01	30.3
2003-07-01	30.3
2003-10-01	30.3
2004-01-01	30.4
2004-04-01	30.4
2004-07-01	30.4
2004-10-01	30.4
2005-01-01	31.7
2005-04-01	31.7
2005-07-01	31.7
2005-10-01	31.7
2006-01-01	33.2
2006-04-01	33.2
2006-07-01	33.2
2006-10-01	33.2
2007-01-01	30
2007-04-01	33.4
2007-07-01	34.8
2007-10-01	29.8
2008-01-01	30.6
2008-04-01	38.3
2008-07-01	36.5
2008-10-01	30.9
2009-01-01	37.1
2009-04-01	41.4
2009-07-01	37.6
2009-10-01	36.7
2010-01-01	38.1
2010-04-01	42.4
2010-07-01	38.4
2010-10-01	39.7
2011-01-01	38.6
2011-04-01	37.7
2011-07-01	43
2011-10-01	37.9
2012-01-01	41.3
2012-04-01	40.1
2012-07-01	42.3
2012-10-01	40.3
2013-01-01	40.3
2013-04-01	44.8
2013-07-01	39
2013-10-01	37.7
2014-01-01	40.4
2014-04-01	43.8
2014-07-01	43.2
2014-10-01	42.8
2015-01-01	42.1
2015-04-01	40.1
2015-07-01	34.1
2015-10-01	37.5
2016-01-01	40.1
2016-04-01	39.7
2016-07-01	38.4
2016-10-01	40.0
2017-01-01	40.5
2017-04-01	39.1
2017-07-01	39.8
2017-10-01	39.6
2018-01-01	39.0
2018-04-01	39.6