Quarter	Percent
1998-04-01	33.9
1999-01-01	35.1
1999-04-01	36.8
1999-07-01	34.9
1999-10-01	34.6
2000-01-01	37.7
2000-04-01	36.3
2000-07-01	38.6
2000-10-01	37.4
2001-01-01	35.5
2001-04-01	36.6
2001-07-01	36.2
2001-10-01	37
2002-01-01	37.8
2002-04-01	36.3
2002-07-01	38.5
2002-10-01	37.2
2003-01-01	35.2
2003-04-01	39.4
2003-07-01	39.5
2003-10-01	41.4
2004-01-01	39.7
2004-04-01	41
2004-07-01	40.9
2004-10-01	39.8
2005-01-01	42.4
2005-04-01	43.2
2005-07-01	45.4
2005-10-01	42.6
2006-01-01	42.2
2006-04-01	40.1
2006-07-01	42.5
2006-10-01	46
2007-01-01	46.3
2007-04-01	42.2
2007-07-01	44.7
2007-10-01	44.7
2008-01-01	44.4
2008-04-01	42.8
2008-07-01	45
2008-10-01	45.6
2009-01-01	44.7
2009-04-01	43.9
2009-07-01	45.6
2009-10-01	46.4
2010-01-01	45.8
2010-04-01	48.1
2010-07-01	47.5
2010-10-01	48.9
2011-01-01	46.5
2011-04-01	48.5
2011-07-01	47.7
2011-10-01	48.6
2012-01-01	47.6
2012-04-01	48
2012-07-01	48.4
2012-10-01	47.6
2013-01-01	49.6
2013-04-01	51.4
2013-07-01	51.1
2013-10-01	49.9
2014-01-01	50.5
2014-04-01	52.1
2014-07-01	49.4
2014-10-01	53.1
2015-01-01	51.6
2015-04-01	51.9
2015-07-01	53.3
2015-10-01	51.9
2016-01-01	51.5
2016-04-01	55.0
2016-07-01	54.1
2016-10-01	53.8
2017-01-01	55.5
2017-04-01	55.8
2017-07-01	56.4
2017-10-01	59.8
2018-01-01	58.5
2018-04-01	57.5