Quarter	Percent
1999-04-01	46.3
1999-07-01	55.7
1999-10-01	48.7
2000-01-01	47.6
2000-04-01	48.1
2000-07-01	56.8
2000-10-01	49.2
2001-01-01	48.2
2001-04-01	46.8
2001-07-01	54.9
2001-10-01	47.5
2002-01-01	46.3
2002-04-01	44.9
2002-07-01	52.4
2002-10-01	46.6
2003-01-01	45.6
2003-04-01	45.4
2003-07-01	51.9
2003-10-01	47.1
2004-01-01	46.2
2004-04-01	44.8
2004-07-01	52.1
2004-10-01	47.8
2005-01-01	46.8
2005-04-01	46.3
2005-07-01	53.3
2005-10-01	48.4
2006-01-01	47.8
2006-04-01	48.4
2006-07-01	54.6
2006-10-01	50.2
2007-01-01	61.8
2007-04-01	62.3
2007-07-01	66.3
2007-10-01	61.7
2008-01-01	58.6
2008-04-01	58.5
2008-07-01	59.4
2008-10-01	51.8
2009-01-01	47.7
2009-04-01	46.1
2009-07-01	45.3
2009-10-01	42.1
2010-01-01	38.4
2010-04-01	39.2
2010-07-01	40.0
2010-10-01	37.2
2011-01-01	35.8
2011-04-01	36.1
2011-07-01	36.9
2011-10-01	35.8
2012-01-01	33.3
2012-04-01	34.4
2012-07-01	36.7
2012-10-01	34.9
2013-01-01	33.9
2013-04-01	36.2
2013-07-01	39.4
2013-10-01	36.7
2014-01-01	34.0
2014-04-01	35.0
2014-07-01	40.0
2014-10-01	38.2
2015-01-01	35.7
2015-04-01	37.1
2015-07-01	40.8
2015-10-01	37.8
2016-01-01	37.3
2016-04-01	43.0
2016-07-01	45.9
2016-10-01	42.1
2017-01-01	39.6
2017-04-01	41.0
2017-07-01	39.4
2017-10-01	39.9
2018-01-01	37.4
2018-04-01	40.1