Quarter	Percent
1998-04-01	70.4
1998-10-01	71.3
1999-04-01	70.6
1999-10-01	71.3
2000-04-01	72.0
2000-10-01	69.6
2001-04-01	67.5
2001-10-01	66.4
2002-01-01	64.9
2002-04-01	60.5
2002-07-01	61.4
2002-10-01	58.7
2003-01-01	62.6
2003-04-01	59.6
2003-07-01	55.1
2003-10-01	57.2
2004-01-01	54.5
2004-04-01	54.1
2004-07-01	54.7
2004-10-01	53.3
2005-01-01	52.7
2005-04-01	55.1
2005-07-01	50.3
2005-10-01	50.0
2006-01-01	48.5
2006-04-01	49.6
2006-07-01	44.7
2006-10-01	48.8
2007-01-01	44.1
2007-04-01	44.0
2007-07-01	44.9
2007-10-01	44.3
2008-01-01	41.1
2008-04-01	40.4
2008-07-01	42.0
2008-10-01	39.6
2009-01-01	37.2
2009-04-01	36.0
2009-07-01	45.0
2009-10-01	43.8
2010-01-01	43.0
2010-04-01	42.5
2010-07-01	44.6
2010-10-01	47.1
2011-01-01	45.1
2011-04-01	42.1
2011-07-01	43.5
2011-10-01	40.9
2012-01-01	39.8
2012-04-01	38.5
2012-07-01	37.8
2012-10-01	40.5
2013-01-01	40.8
2013-04-01	37.6
2013-07-01	39.2
2013-10-01	40.4
2014-01-01	36.1
2014-04-01	38.1
2014-07-01	39.2
2014-10-01	39.9
2015-01-01	36.9
2015-04-01	36.7
2015-07-01	35.3
2015-10-01	37.0
2016-01-01	34.6
2016-04-01	31.6
2016-07-01	36.2
2016-10-01	33.3
2017-01-01	35.0
2017-04-01	32.3
2017-07-01	32.9
2017-10-01	32.3
2018-01-01	32.3
2018-04-01	30.1