Quarter	Percent
1998-01-01	44.9
1998-04-01	44.6
1998-07-01	45.2
1998-10-01	44.9
1999-01-01	44.3
1999-04-01	44.1
1999-07-01	43.5
1999-10-01	43.4
2000-01-01	44.6
2000-04-01	45.5
2000-07-01	45.4
2000-10-01	46.5
2001-01-01	45.9
2001-04-01	45.3
2001-07-01	45.2
2001-10-01	43.7
2002-01-01	42.2
2002-04-01	41.7
2002-07-01	39.8
2002-10-01	39.3
2003-01-01	39.7
2003-04-01	40.5
2003-07-01	39.7
2003-10-01	40.4
2004-01-01	40.2
2004-04-01	40.3
2004-07-01	39.5
2004-10-01	39.3
2005-01-01	38.3
2005-04-01	38.1
2005-07-01	36.9
2005-10-01	38.1
2006-01-01	36.5
2006-04-01	37.3
2006-07-01	37.2
2006-10-01	38
2007-01-01	38.2
2007-04-01	38.2
2007-07-01	36.7
2007-10-01	37
2008-01-01	36.5
2008-04-01	35.7
2008-07-01	35.8
2008-10-01	35.4
2009-01-01	35.9
2009-04-01	36.3
2009-07-01	37.1
2009-10-01	38.1
2010-01-01	37.8
2010-04-01	37.7
2010-07-01	37.2
2010-10-01	37.5
2011-01-01	37.5
2011-04-01	36.2
2011-07-01	37.3
2011-10-01	38.6
2012-01-01	38.1
2012-04-01	36.3
2012-07-01	34.7
2012-10-01	34.8
2013-01-01	34.7
2013-04-01	34
2013-07-01	33.5
2013-10-01	33.5
2014-01-01	33.2
2014-04-01	32.8
2014-07-01	31.3
2014-10-01	31
2015-01-01	32.3
2015-04-01	31.6
2015-07-01	31.6
2015-10-01	31.4
2016-01-01	30.4
2016-04-01	29.4
2016-07-01	28.6
2016-10-01	27.8
2017-01-01	28.1
2017-04-01	26.8
2017-07-01	26.6
2017-10-01	25.8
2018-01-01	25.2
2018-04-01	24.6