Quarter	Percent
1999-04-01	58.8
2000-01-01	56.2
2000-04-01	58.1
2000-07-01	59.8
2000-10-01	55.2
2001-01-01	56.8
2001-04-01	53
2001-07-01	53
2001-10-01	52.3
2002-01-01	54.2
2002-04-01	48.6
2002-07-01	46
2002-10-01	48.3
2003-01-01	49.9
2003-04-01	47.3
2003-07-01	50.6
2003-10-01	48.5
2004-01-01	42.3
2004-04-01	43.9
2004-07-01	46.6
2004-10-01	47.2
2005-01-01	44.1
2005-04-01	42.4
2005-07-01	39.8
2005-10-01	43.1
2006-01-01	43.1
2006-04-01	34.8
2006-07-01	38.5
2006-10-01	41.2
2007-01-01	37.1
2007-04-01	34
2007-07-01	41.1
2007-10-01	42.9
2008-01-01	39.7
2008-04-01	38.1
2008-07-01	37.9
2008-10-01	34.6
2009-01-01	33.1
2009-04-01	34.5
2009-07-01	33.6
2009-10-01	34.9
2010-01-01	34.9
2010-04-01	35.8
2010-07-01	34.2
2010-10-01	38.1
2011-01-01	36.1
2011-04-01	35.8
2011-07-01	38.2
2011-10-01	35.6
2012-01-01	33.2
2012-04-01	32.9
2012-07-01	34.2
2012-10-01	39.9
2013-01-01	33
2013-04-01	28.6
2013-07-01	34.6
2013-10-01	37.9
2014-01-01	37.6
2014-04-01	34.6
2014-07-01	29.6
2014-10-01	32.1
2015-01-01	34.8
2015-04-01	31.0
2015-07-01	25.5
2015-10-01	30.9
2016-01-01	31.4
2016-04-01	26.5
2016-07-01	26.6
2016-10-01	29.9
2017-01-01	29.1
2017-04-01	29.6
2017-07-01	27.7
2017-10-01	24.1
2018-01-01	24.7
2018-04-01	27.1