Quarter	Percent
1998-01-01	17.1
1999-01-01	17.6
1999-04-01	16.8
1999-07-01	16.5
1999-10-01	14.5
2000-01-01	17.8
2000-04-01	17.2
2000-07-01	16
2000-10-01	17.6
2001-01-01	17.4
2001-04-01	18.4
2001-07-01	16.9
2001-10-01	19
2002-01-01	18.6
2002-04-01	19
2002-07-01	19.5
2002-10-01	20
2003-01-01	19.4
2003-04-01	21.4
2003-07-01	20.9
2003-10-01	21.4
2004-01-01	17.2
2004-04-01	17.9
2004-07-01	18
2004-10-01	19.6
2005-01-01	20
2005-04-01	21.8
2005-07-01	22.9
2005-10-01	22.5
2006-01-01	23.6
2006-04-01	24.3
2006-07-01	24.6
2006-10-01	25.7
2007-01-01	25.9
2007-04-01	25.8
2007-07-01	26.6
2007-10-01	27.7
2008-01-01	28.8
2008-04-01	28.7
2008-07-01	30.3
2008-10-01	29.3
2009-01-01	29.6
2009-04-01	29.6
2009-07-01	30.3
2009-10-01	31.8
2010-01-01	32.9
2010-04-01	33.3
2010-07-01	33.7
2010-10-01	32
2011-01-01	32.2
2011-04-01	32.4
2011-07-01	32.6
2011-10-01	31.5
2012-01-01	32.5
2012-04-01	33.8
2012-07-01	33.7
2012-10-01	34.1
2013-01-01	34.1
2013-04-01	36
2013-07-01	35.6
2013-10-01	35.2
2014-01-01	35
2014-04-01	36.8
2014-07-01	36.9
2014-10-01	36.9
2015-01-01	37.3
2015-04-01	39.1
2015-07-01	39.4
2015-10-01	39.5
2016-01-01	39.7
2016-04-01	41.7
2016-07-01	41.5
2016-10-01	41.5
2017-01-01	41.6
2017-04-01	42.0
2017-07-01	43.8
2017-10-01	43.8
2018-01-01	44.8
2018-04-01	44.0