Quarter	Percent
1998-01-01	29.5
1998-04-01	32.5
1998-07-01	42.4
1998-10-01	32.8
1999-01-01	32.3
1999-04-01	45
1999-07-01	47.3
1999-10-01	35.4
2000-01-01	34.5
2000-04-01	45.4
2000-07-01	48
2000-10-01	36.5
2001-01-01	35.7
2001-04-01	46.2
2001-07-01	47.8
2001-10-01	37.5
2002-01-01	34.2
2002-04-01	44.8
2002-07-01	47.1
2002-10-01	36.6
2003-01-01	35
2003-04-01	44.3
2003-07-01	45.7
2003-10-01	33.5
2004-01-01	32.9
2004-04-01	43.3
2004-07-01	45.7
2004-10-01	35.7
2005-01-01	34.7
2005-04-01	44
2005-07-01	45.3
2005-10-01	38
2006-01-01	36.4
2006-04-01	45
2006-07-01	48.1
2006-10-01	38.9
2007-01-01	36.9
2007-04-01	48.6
2007-07-01	51
2007-10-01	41.9
2008-01-01	39.3
2008-04-01	49.8
2008-07-01	48.9
2008-10-01	40.8
2009-01-01	37.6
2009-04-01	44.6
2009-07-01	41.7
2009-10-01	34.5
2010-01-01	33
2010-04-01	43
2010-07-01	43.6
2010-10-01	35.6
2011-01-01	34.6
2011-04-01	45.4
2011-07-01	45.4
2011-10-01	36.1
2012-01-01	35.6
2012-04-01	46.8
2012-07-01	46.7
2012-10-01	38.1
2013-01-01	36.3
2013-04-01	46.1
2013-07-01	45.3
2013-10-01	38.4
2014-01-01	35.9
2014-04-01	46.3
2014-07-01	45.6
2014-10-01	37.6
2015-01-01	36.0
2015-04-01	44.6
2015-07-01	44.9
2015-10-01	36.4
2016-01-01	36.2
2016-04-01	45.5
2016-07-01	46.6
2016-10-01	38.3
2017-01-01	36.7
2017-04-01	45.2
2017-07-01	48.0
2017-10-01	40.2
2018-01-01	38.7
2018-04-01	49.6