Quarter	Percent
1999-01-01	31.8
1999-04-01	34.7
1999-07-01	40
1999-10-01	36.6
2000-01-01	32.8
2000-04-01	34.7
2000-07-01	39
2000-10-01	36
2001-01-01	32.2
2001-04-01	34.1
2001-07-01	38.2
2001-10-01	32.3
2002-01-01	34.9
2002-04-01	34.8
2002-07-01	36.1
2002-10-01	31.7
2003-01-01	31.7
2003-04-01	33.3
2003-07-01	33.7
2003-10-01	35.9
2004-01-01	36.4
2004-04-01	38.3
2004-07-01	43
2004-10-01	37.8
2005-01-01	38.6
2005-04-01	36.4
2005-07-01	40.5
2005-10-01	36.7
2006-01-01	36.2
2006-04-01	38.5
2006-07-01	45.1
2006-10-01	37.1
2007-01-01	40.4
2007-04-01	42.8
2007-07-01	48.5
2007-10-01	41.1
2008-01-01	38.5
2008-04-01	42.6
2008-07-01	49.5
2008-10-01	41.2
2009-01-01	35.1
2009-04-01	38.7
2009-07-01	44.5
2009-10-01	38.1
2010-01-01	36.6
2010-04-01	35.2
2010-07-01	40.8
2010-10-01	37.9
2011-01-01	33.2
2011-04-01	35.1
2011-07-01	40.1
2011-10-01	34.2
2012-01-01	29.8
2012-04-01	30.7
2012-07-01	32.1
2012-10-01	29
2013-01-01	27.3
2013-04-01	29.8
2013-07-01	32.5
2013-10-01	29.1
2014-01-01	25.8
2014-04-01	29.2
2014-07-01	31.9
2014-10-01	31.0
2015-01-01	29.9
2015-04-01	30.5
2015-07-01	36.7
2015-10-01	31.0
2016-01-01	28.6
2016-04-01	29.5
2016-07-01	34.2
2016-10-01	31.9
2017-01-01	34.5
2017-04-01	38.7
2017-07-01	45.1
2017-10-01	36.1
2018-01-01	36.8
2018-04-01	41.9