Quarter	Percent
1999-01-01	25.2
1999-04-01	24.8
1999-07-01	24
1999-10-01	24.3
2000-01-01	24.6
2000-04-01	24.6
2000-07-01	23.8
2000-10-01	24.3
2001-01-01	24.7
2001-04-01	25.4
2001-07-01	25.7
2001-10-01	26.1
2002-01-01	26.7
2002-04-01	26.4
2002-07-01	26.9
2002-10-01	27.7
2003-01-01	27.2
2003-04-01	28.1
2003-07-01	29.2
2003-10-01	29.4
2004-01-01	30
2004-04-01	31.1
2004-07-01	32.6
2004-10-01	33
2005-01-01	33.6
2005-04-01	34.4
2005-07-01	35.7
2005-10-01	36.3
2006-01-01	36.2
2006-04-01	36.4
2006-07-01	37
2006-10-01	37.1
2007-01-01	37.5
2007-04-01	38.3
2007-07-01	39.6
2007-10-01	39.8
2008-01-01	40.6
2008-04-01	41.2
2008-07-01	43.1
2008-10-01	42.7
2009-01-01	42
2009-04-01	42.6
2009-07-01	43.5
2009-10-01	43.2
2010-01-01	44.7
2010-04-01	45.5
2010-07-01	45.2
2010-10-01	44.9
2011-01-01	44.7
2011-04-01	45.8
2011-07-01	46.5
2011-10-01	46.8
2012-01-01	47.4
2012-04-01	48.6
2012-07-01	48.5
2012-10-01	49.5
2013-01-01	49.5
2013-04-01	49.7
2013-07-01	49.5
2013-10-01	49.2
2014-01-01	49
2014-04-01	49.7
2014-07-01	50.5
2014-10-01	51.1
2015-01-01	51.2
2015-04-01	51.1
2015-07-01	52.0
2015-10-01	52.9
2016-01-01	52.5
2016-04-01	54.6
2016-07-01	53.8
2016-10-01	54.6
2017-01-01	55.1
2017-04-01	56.4
2017-07-01	56.5
2017-10-01	57.4
2018-01-01	57.0
2018-04-01	56.5