Quarter	Percent
1999-01-01	26.1
1999-04-01	22.9
1999-07-01	21.9
1999-10-01	22.3
2000-01-01	21.8
2000-04-01	19.6
2000-07-01	20.2
2000-10-01	20.2
2001-01-01	17.1
2001-04-01	16.4
2001-07-01	16.3
2001-10-01	16.8
2002-01-01	18.4
2002-04-01	16.8
2002-07-01	18.7
2002-10-01	20.1
2003-01-01	20.1
2003-04-01	19.2
2003-07-01	19.1
2003-10-01	19.6
2004-01-01	19.4
2004-04-01	19.4
2004-07-01	18.4
2004-10-01	17.7
2005-01-01	18.5
2005-04-01	17.4
2005-07-01	15
2005-10-01	16
2006-01-01	16.7
2006-04-01	15.3
2006-07-01	13.9
2006-10-01	14.1
2007-01-01	14.1
2007-04-01	15.1
2007-07-01	15.2
2007-10-01	16.5
2008-01-01	19.3
2008-04-01	21.9
2008-07-01	23.7
2008-10-01	29.6
2009-01-01	36.2
2009-04-01	40
2009-07-01	39.4
2009-10-01	40.8
2010-01-01	43.2
2010-04-01	43.3
2010-07-01	41.4
2010-10-01	44.5
2011-01-01	47.4
2011-04-01	48.1
2011-07-01	47
2011-10-01	50.2
2012-01-01	53.8
2012-04-01	54.3
2012-07-01	52.7
2012-10-01	55.9
2013-01-01	59.1
2013-04-01	56.3
2013-07-01	54
2013-10-01	55.6
2014-01-01	56
2014-04-01	53.8
2014-07-01	52.3
2014-10-01	51.6
2015-01-01	52.6
2015-04-01	50.0
2015-07-01	46.7
2015-10-01	45.4
2016-01-01	45.7
2016-04-01	45.8
2016-07-01	41.9
2016-10-01	42.8
2017-01-01	42.6
2017-04-01	40.6
2017-07-01	37.4
2017-10-01	37.8
2018-01-01	38.0
2018-04-01	35.5
2018-07-01	34.0