Quarter	Percent
1999-01-01	24
1999-04-01	24.3
1999-07-01	22.2
1999-10-01	21.9
2000-01-01	22.7
2000-04-01	23.7
2000-07-01	25.4
2000-10-01	24.3
2001-01-01	25.7
2001-04-01	24.6
2001-07-01	27.5
2001-10-01	28.1
2002-01-01	26.8
2002-04-01	26.6
2002-07-01	24.5
2002-10-01	23
2003-01-01	23.9
2003-04-01	23.6
2003-07-01	22.8
2003-10-01	26.6
2004-01-01	27.7
2004-04-01	31.1
2004-07-01	31.2
2004-10-01	29.7
2005-01-01	29.5
2005-04-01	32.5
2005-07-01	33.4
2005-10-01	32.8
2006-01-01	33.3
2006-04-01	34.5
2006-07-01	33.4
2006-10-01	32.5
2007-01-01	31.8
2007-04-01	36
2007-07-01	36.3
2007-10-01	34.1
2008-01-01	32.6
2008-04-01	35.1
2008-07-01	34.5
2008-10-01	34.4
2009-01-01	34.3
2009-04-01	37.7
2009-07-01	38.4
2009-10-01	37.1
2010-01-01	36.1
2010-04-01	37
2010-07-01	37.1
2010-10-01	35.7
2011-01-01	31.7
2011-04-01	33.1
2011-07-01	34.8
2011-10-01	33.6
2012-01-01	33.6
2012-04-01	35.1
2012-07-01	35.1
2012-10-01	36.4
2013-01-01	35.2
2013-04-01	36.8
2013-07-01	36.4
2013-10-01	35.6
2014-01-01	35.9
2014-04-01	39.3
2014-07-01	39.6
2014-10-01	38.9
2015-01-01	38.0
2015-04-01	40.9
2015-07-01	40.6
2015-10-01	39.1
2016-01-01	40.5
2016-04-01	42.2
2016-07-01	40.0
2016-10-01	42.1
2017-01-01	43.8
2017-04-01	46.3
2017-07-01	45.9
2017-10-01	46.6
2018-01-01	46.8
2018-04-01	50.3