Quarter	Percent
1998-01-01	14.8
1998-04-01	14.8
1998-07-01	15.1
1998-10-01	15.1
1999-01-01	14.9
1999-04-01	15
1999-07-01	15.2
1999-10-01	14.9
2000-01-01	14.7
2000-04-01	15.2
2000-07-01	15.4
2000-10-01	16
2001-01-01	16.1
2001-04-01	15.3
2001-07-01	16.5
2001-10-01	17.2
2002-01-01	16.5
2002-04-01	16.9
2002-07-01	17.9
2002-10-01	17.9
2003-01-01	17.1
2003-04-01	18.1
2003-07-01	19.2
2003-10-01	19.3
2004-01-01	18.2
2004-04-01	18.9
2004-07-01	20.5
2004-10-01	21.1
2005-01-01	20.4
2005-04-01	20.6
2005-07-01	20.7
2005-10-01	21.5
2006-01-01	21
2006-04-01	22.1
2006-07-01	22.1
2006-10-01	22.1
2007-01-01	22.4
2007-04-01	23.5
2007-07-01	23.1
2007-10-01	22.8
2008-01-01	22.6
2008-04-01	24.6
2008-07-01	24.3
2008-10-01	24.1
2009-01-01	24.6
2009-04-01	26.3
2009-07-01	25.2
2009-10-01	24.9
2010-01-01	25.7
2010-04-01	26.1
2010-07-01	26.2
2010-10-01	26.3
2011-01-01	27.4
2011-04-01	27.4
2011-07-01	28.3
2011-10-01	29.1
2012-01-01	29.9
2012-04-01	30.7
2012-07-01	31.1
2012-10-01	31.6
2013-01-01	31.5
2013-04-01	32.6
2013-07-01	34
2013-10-01	34.7
2014-01-01	35.3
2014-04-01	36
2014-07-01	37.4
2014-10-01	37.6
2015-01-01	37.4
2015-04-01	38.2
2015-07-01	37.9
2015-10-01	38.1
2016-01-01	38.6
2016-04-01	40.0
2016-07-01	39.8
2016-10-01	40.6
2017-01-01	41.4
2017-04-01	42.5
2017-07-01	42.1
2017-10-01	43.2
2018-01-01	43.7
2018-04-01	44.5