Quarter	Percent
1998-04-01	36.3
1998-10-01	39.2
1999-04-01	36.6
1999-10-01	36.5
2000-04-01	35.4
2000-10-01	33.2
2001-04-01	32.9
2001-10-01	31.2
2002-01-01	36.2
2002-04-01	31.2
2002-07-01	40.2
2002-10-01	37.8
2003-01-01	35.7
2003-04-01	37.9
2003-07-01	34.7
2003-10-01	36.9
2004-01-01	35.0
2004-04-01	36.3
2004-07-01	37.9
2004-10-01	37.6
2005-01-01	37.9
2005-04-01	33.3
2005-07-01	41.8
2005-10-01	40.0
2006-01-01	40.5
2006-04-01	35.6
2006-07-01	47.8
2006-10-01	43.5
2007-01-01	42.1
2007-04-01	41.4
2007-07-01	46.2
2007-10-01	45.5
2008-01-01	43.4
2008-04-01	43.0
2008-07-01	45.0
2008-10-01	36.9
2009-01-01	31.7
2009-04-01	31.2
2009-07-01	29.4
2009-10-01	25.7
2010-01-01	24.7
2010-04-01	25.2
2010-07-01	28.3
2010-10-01	27.7
2011-01-01	27.4
2011-04-01	28.4
2011-07-01	28.4
2011-10-01	29.0
2012-01-01	29.5
2012-04-01	30.8
2012-07-01	32.8
2012-10-01	34.1
2013-01-01	33.8
2013-04-01	32.3
2013-07-01	32.6
2013-10-01	34.3
2014-01-01	35.5
2014-04-01	33.7
2014-07-01	37.8
2014-10-01	39.1
2015-01-01	36.3
2015-04-01	37.0
2015-07-01	37.1
2015-10-01	38.0
2016-01-01	35.4
2016-04-01	33.6
2016-07-01	35.4
2016-10-01	31.6
2017-01-01	32.7
2017-04-01	37.0
2017-07-01	38.0
2017-10-01	32.3
2018-01-01	32.2
2018-04-01	34.2