Quarter	Percent
1999-04-01	17.7
2000-04-01	16.8
2001-04-01	14.4
2002-04-01	18.1
2003-01-01	21.2
2003-04-01	21.2
2003-07-01	21.2
2003-10-01	21.2
2004-01-01	22.6
2004-04-01	22.6
2004-07-01	22.6
2004-10-01	22.6
2005-01-01	25.1
2005-04-01	25.1
2005-07-01	25.1
2005-10-01	25.1
2006-01-01	28.5
2006-04-01	28.5
2006-07-01	28.5
2006-10-01	28.5
2007-01-01	28.4
2007-04-01	27.4
2007-07-01	32.3
2007-10-01	28.4
2008-01-01	32.2
2008-04-01	32.5
2008-07-01	30.8
2008-10-01	25.6
2009-01-01	27.9
2009-04-01	32
2009-07-01	30.4
2009-10-01	32.1
2010-01-01	30
2010-04-01	34.6
2010-07-01	29.8
2010-10-01	33.5
2011-01-01	32.5
2011-04-01	32.5
2011-07-01	35.2
2011-10-01	28.2
2012-01-01	34.6
2012-04-01	35.9
2012-07-01	38.2
2012-10-01	32.2
2013-01-01	30.2
2013-04-01	41.5
2013-07-01	33.7
2013-10-01	31.4
2014-01-01	38.6
2014-04-01	35.3
2014-07-01	37.1
2014-10-01	35.1
2015-01-01	38.5
2015-04-01	34.9
2015-07-01	31.0
2015-10-01	35.7
2016-01-01	36.1
2016-04-01	32.3
2016-07-01	32.2
2016-10-01	34.9
2017-01-01	33.8
2017-04-01	33.8
2017-07-01	36.0
2017-10-01	36.8
2018-01-01	35.5
2018-04-01	36.0