Quarter	Percent
1999-01-01	37.8
1999-04-01	40.4
1999-07-01	44.9
1999-10-01	42
2000-01-01	36.9
2000-04-01	37.3
2000-07-01	43.4
2000-10-01	39
2001-01-01	36.3
2001-04-01	36
2001-07-01	40
2001-10-01	36.3
2002-01-01	37.1
2002-04-01	36.6
2002-07-01	38.2
2002-10-01	34.5
2003-01-01	34.2
2003-04-01	33.8
2003-07-01	35.5
2003-10-01	37.4
2004-01-01	38.3
2004-04-01	39.3
2004-07-01	43.5
2004-10-01	40.3
2005-01-01	40.3
2005-04-01	36.5
2005-07-01	44.2
2005-10-01	41.1
2006-01-01	39.1
2006-04-01	41.3
2006-07-01	44
2006-10-01	38.1
2007-01-01	39
2007-04-01	40.4
2007-07-01	47.1
2007-10-01	40.8
2008-01-01	39.4
2008-04-01	41.1
2008-07-01	49.5
2008-10-01	41.5
2009-01-01	36.5
2009-04-01	39.6
2009-07-01	47.5
2009-10-01	39.8
2010-01-01	39.2
2010-04-01	39.1
2010-07-01	41.9
2010-10-01	39.5
2011-01-01	35.2
2011-04-01	35.6
2011-07-01	40.2
2011-10-01	38.6
2012-01-01	34.5
2012-04-01	31.2
2012-07-01	37
2012-10-01	34.8
2013-01-01	32.2
2013-04-01	33.9
2013-07-01	37.7
2013-10-01	31.6
2014-01-01	30.3
2014-04-01	33
2014-07-01	36.3
2014-10-01	34.8
2015-01-01	32.2
2015-04-01	35.5
2015-07-01	38.8
2015-10-01	34.9
2016-01-01	31.3
2016-04-01	32.3
2016-07-01	36.8
2016-10-01	34.5
2017-01-01	35.8
2017-04-01	38.3
2017-07-01	44.4
2017-10-01	38.1
2018-01-01	37.9
2018-04-01	40.3