Quarter	Percent
1998-04-01	59.0
1998-10-01	60.1
1999-04-01	60.1
1999-10-01	60.0
2000-04-01	61.0
2000-10-01	59.5
2001-04-01	59.1
2001-10-01	57.9
2002-01-01	56.1
2002-04-01	52.5
2002-07-01	53.4
2002-10-01	52.4
2003-01-01	54.8
2003-04-01	54.6
2003-07-01	47.8
2003-10-01	53.3
2004-01-01	47.1
2004-04-01	50.2
2004-07-01	47.6
2004-10-01	48.8
2005-01-01	47.2
2005-04-01	49.4
2005-07-01	45.4
2005-10-01	45.7
2006-01-01	43.4
2006-04-01	44.0
2006-07-01	40.3
2006-10-01	43.2
2007-01-01	39.9
2007-04-01	40.2
2007-07-01	39.6
2007-10-01	37.4
2008-01-01	36.8
2008-04-01	36.5
2008-07-01	37.6
2008-10-01	37.0
2009-01-01	35.8
2009-04-01	34.0
2009-07-01	43.7
2009-10-01	42.9
2010-01-01	43.8
2010-04-01	40.1
2010-07-01	43.4
2010-10-01	45.2
2011-01-01	42.4
2011-04-01	39.8
2011-07-01	41.0
2011-10-01	39.0
2012-01-01	39.9
2012-04-01	37.0
2012-07-01	37.1
2012-10-01	38.6
2013-01-01	40.3
2013-04-01	37.4
2013-07-01	37.8
2013-10-01	39.4
2014-01-01	36.6
2014-04-01	37.2
2014-07-01	38.6
2014-10-01	37.5
2015-01-01	35.2
2015-04-01	35.4
2015-07-01	34.1
2015-10-01	33.4
2016-01-01	32.6
2016-04-01	31.4
2016-07-01	33.7
2016-10-01	31.9
2017-01-01	33.6
2017-04-01	31.9
2017-07-01	32.3
2017-10-01	30.8
2018-01-01	30.9
2018-04-01	28.3