Quarter	Percent
1999-01-01	33.2
1999-04-01	33.9
1999-07-01	33
1999-10-01	32
2000-01-01	33.2
2000-04-01	33.5
2000-07-01	37.3
2000-10-01	34.5
2001-01-01	36.7
2001-04-01	34.8
2001-07-01	38.4
2001-10-01	40.1
2002-01-01	38.6
2002-04-01	38.4
2002-07-01	35.6
2002-10-01	34.2
2003-01-01	33.5
2003-04-01	33.2
2003-07-01	33.2
2003-10-01	38.1
2004-01-01	39.7
2004-04-01	42.7
2004-07-01	43.5
2004-10-01	44.2
2005-01-01	43.1
2005-04-01	45
2005-07-01	47.5
2005-10-01	46
2006-01-01	47
2006-04-01	46.4
2006-07-01	44.6
2006-10-01	45.1
2007-01-01	42.6
2007-04-01	48
2007-07-01	48.9
2007-10-01	47
2008-01-01	44.9
2008-04-01	48
2008-07-01	46.5
2008-10-01	46.1
2009-01-01	45.7
2009-04-01	49.9
2009-07-01	49
2009-10-01	48.2
2010-01-01	48.6
2010-04-01	46.9
2010-07-01	48.9
2010-10-01	45.8
2011-01-01	41.9
2011-04-01	42.8
2011-07-01	43.8
2011-10-01	42.2
2012-01-01	42.3
2012-04-01	42.6
2012-07-01	44
2012-10-01	45.6
2013-01-01	44.7
2013-04-01	45.2
2013-07-01	45.9
2013-10-01	44.7
2014-01-01	42.7
2014-04-01	46.3
2014-07-01	46.8
2014-10-01	47
2015-01-01	45.0
2015-04-01	48.1
2015-07-01	46.8
2015-10-01	45.5
2016-01-01	45.2
2016-04-01	48.1
2016-07-01	46.9
2016-10-01	48.2
2017-01-01	49.8
2017-04-01	52.3
2017-07-01	52.6
2017-10-01	52.4
2018-01-01	52.1
2018-04-01	55.2