Quarter	Percent
1999-01-01	30.8
1999-04-01	32.2
1999-07-01	31.1
1999-10-01	30.1
2000-01-01	30.7
2000-04-01	31
2000-07-01	35.1
2000-10-01	32.7
2001-01-01	35.3
2001-04-01	33
2001-07-01	37.2
2001-10-01	37.9
2002-01-01	36.8
2002-04-01	37.4
2002-07-01	34.5
2002-10-01	33
2003-01-01	32
2003-04-01	31.8
2003-07-01	31.9
2003-10-01	37.1
2004-01-01	37.7
2004-04-01	41.2
2004-07-01	42
2004-10-01	42.7
2005-01-01	41.5
2005-04-01	42.5
2005-07-01	44.9
2005-10-01	43.7
2006-01-01	45.6
2006-04-01	45.2
2006-07-01	43.8
2006-10-01	43.6
2007-01-01	41.5
2007-04-01	46.5
2007-07-01	47.1
2007-10-01	45.8
2008-01-01	43.4
2008-04-01	46
2008-07-01	45.4
2008-10-01	44
2009-01-01	43.3
2009-04-01	47.7
2009-07-01	47.7
2009-10-01	46.8
2010-01-01	47.7
2010-04-01	44.8
2010-07-01	47.3
2010-10-01	42.6
2011-01-01	39.3
2011-04-01	39.2
2011-07-01	40.1
2011-10-01	39.3
2012-01-01	39
2012-04-01	39.7
2012-07-01	41.3
2012-10-01	43
2013-01-01	40.2
2013-04-01	42
2013-07-01	43
2013-10-01	41.9
2014-01-01	39.2
2014-04-01	42.9
2014-07-01	42.5
2014-10-01	42.4
2015-01-01	41.4
2015-04-01	44.4
2015-07-01	42.8
2015-10-01	41.8
2016-01-01	42.2
2016-04-01	44.9
2016-07-01	43.9
2016-10-01	43.3
2017-01-01	45.3
2017-04-01	48.9
2017-07-01	48.7
2017-10-01	49.1
2018-01-01	48.9
2018-04-01	52.0