Quarter	Percent
1998-01-01	23
1998-04-01	21.1
1998-07-01	21.1
1998-10-01	22
1999-01-01	23.7
1999-04-01	22.8
1999-07-01	22.6
1999-10-01	23.1
2000-01-01	22.7
2000-04-01	21.9
2000-07-01	21.1
2000-10-01	20.8
2001-01-01	21.8
2001-04-01	21
2001-07-01	21.2
2001-10-01	22.5
2002-01-01	21
2002-04-01	18.7
2002-07-01	18.9
2002-10-01	19.7
2003-01-01	19.4
2003-04-01	17.8
2003-07-01	18.6
2003-10-01	19.3
2004-01-01	20.8
2004-04-01	18.7
2004-07-01	17.6
2004-10-01	18.7
2005-01-01	18.9
2005-04-01	17.6
2005-07-01	19.7
2005-10-01	19.5
2006-01-01	17.9
2006-04-01	17.1
2006-07-01	16.7
2006-10-01	18.6
2007-01-01	17.9
2007-04-01	13.7
2007-07-01	14.1
2007-10-01	16.3
2008-01-01	18
2008-04-01	15
2008-07-01	16.1
2008-10-01	18.5
2009-01-01	19.9
2009-04-01	18.1
2009-07-01	18.1
2009-10-01	22
2010-01-01	24.2
2010-04-01	25
2010-07-01	26.1
2010-10-01	32.2
2011-01-01	34.2
2011-04-01	36.9
2011-07-01	40
2011-10-01	44.3
2012-01-01	46.2
2012-04-01	46.9
2012-07-01	48.8
2012-10-01	51.9
2013-01-01	55.1
2013-04-01	54.5
2013-07-01	53
2013-10-01	52.5
2014-01-01	52.6
2014-04-01	47.1
2014-07-01	43.3
2014-10-01	46.6
2015-01-01	47.5
2015-04-01	45.4
2015-07-01	43.7
2015-10-01	44.1
2016-01-01	47.4
2016-04-01	46.1
2016-07-01	41.7
2016-10-01	42.2
2017-01-01	42.6
2017-04-01	39.3
2017-07-01	36.4
2017-10-01	39.2
2018-01-01	40.7
2018-04-01	35.4