Quarter	Percent
1998-01-01	45.8
1998-04-01	46.4
1998-07-01	46.7
1998-10-01	46.2
1999-01-01	46.3
1999-04-01	46.2
1999-07-01	46.1
1999-10-01	45.5
2000-01-01	45.7
2000-04-01	46.4
2000-07-01	46.6
2000-10-01	46.3
2001-01-01	46
2001-04-01	46.1
2001-07-01	46.1
2001-10-01	45.3
2002-01-01	45.5
2002-04-01	46.6
2002-07-01	46.9
2002-10-01	46.7
2003-01-01	46.7
2003-04-01	47.3
2003-07-01	47.5
2003-10-01	47.1
2004-01-01	46.7
2004-04-01	47.5
2004-07-01	47.5
2004-10-01	47.3
2005-01-01	47.2
2005-04-01	47.8
2005-07-01	47.8
2005-10-01	47.7
2006-01-01	47.9
2006-04-01	48.4
2006-07-01	48.7
2006-10-01	48.2
2007-01-01	48
2007-04-01	48.6
2007-07-01	48.8
2007-10-01	48.5
2008-01-01	48.4
2008-04-01	49.2
2008-07-01	49.2
2008-10-01	48.7
2009-01-01	48.2
2009-04-01	48.6
2009-07-01	48.6
2009-10-01	47.8
2010-01-01	47.2
2010-04-01	47.2
2010-07-01	46.8
2010-10-01	45.6
2011-01-01	44.4
2011-04-01	44
2011-07-01	43.1
2011-10-01	41.5
2012-01-01	40.4
2012-04-01	39.9
2012-07-01	39.3
2012-10-01	38.6
2013-01-01	37.6
2013-04-01	38
2013-07-01	38
2013-10-01	37.4
2014-01-01	37.5
2014-04-01	38.1
2014-07-01	38.7
2014-10-01	38.1
2015-01-01	37.8
2015-04-01	39.2
2015-07-01	39.7
2015-10-01	39.4
2016-01-01	39.1
2016-04-01	40.2
2016-07-01	40.6
2016-10-01	39.7
2017-01-01	39.8
2017-04-01	41.3
2017-07-01	41.7
2017-10-01	40.8
2018-01-01	40.7
2018-04-01	42.2