Quarter	Percent
1998-01-01	15.6
1998-04-01	15.5
1998-07-01	15.8
1998-10-01	15.8
1999-01-01	15.7
1999-04-01	15.9
1999-07-01	16
1999-10-01	15.7
2000-01-01	15.4
2000-04-01	15.9
2000-07-01	16.2
2000-10-01	16.7
2001-01-01	16.7
2001-04-01	16
2001-07-01	17.2
2001-10-01	17.8
2002-01-01	17.3
2002-04-01	17.7
2002-07-01	18.7
2002-10-01	18.8
2003-01-01	18
2003-04-01	19
2003-07-01	20
2003-10-01	20.1
2004-01-01	19.2
2004-04-01	19.8
2004-07-01	21.3
2004-10-01	21.9
2005-01-01	21.1
2005-04-01	21.3
2005-07-01	21.3
2005-10-01	22.3
2006-01-01	21.8
2006-04-01	22.7
2006-07-01	22.7
2006-10-01	22.7
2007-01-01	23
2007-04-01	23.9
2007-07-01	23.6
2007-10-01	23.3
2008-01-01	23.4
2008-04-01	25.4
2008-07-01	25
2008-10-01	24.6
2009-01-01	25.5
2009-04-01	26.9
2009-07-01	25.8
2009-10-01	25.7
2010-01-01	26.6
2010-04-01	26.9
2010-07-01	26.9
2010-10-01	27.2
2011-01-01	28.2
2011-04-01	28.3
2011-07-01	28.9
2011-10-01	29.9
2012-01-01	31.1
2012-04-01	32.2
2012-07-01	32.4
2012-10-01	33
2013-01-01	33
2013-04-01	34.1
2013-07-01	35.4
2013-10-01	36.1
2014-01-01	37
2014-04-01	37.7
2014-07-01	38.8
2014-10-01	39.6
2015-01-01	39.3
2015-04-01	39.9
2015-07-01	39.3
2015-10-01	39.9
2016-01-01	40.7
2016-04-01	42.1
2016-07-01	41.6
2016-10-01	42.5
2017-01-01	43.5
2017-04-01	44.5
2017-07-01	44.4
2017-10-01	45.7
2018-01-01	45.9
2018-04-01	46.8