Quarter	Percent
1998-01-01	18.1
1999-01-01	18.3
1999-04-01	17.3
1999-07-01	16.8
1999-10-01	15
2000-01-01	18.9
2000-04-01	17.8
2000-07-01	16.7
2000-10-01	18.7
2001-01-01	18.3
2001-04-01	19.3
2001-07-01	17.9
2001-10-01	19.6
2002-01-01	19.3
2002-04-01	19.7
2002-07-01	20.6
2002-10-01	20.9
2003-01-01	20.2
2003-04-01	22.7
2003-07-01	21.8
2003-10-01	22.2
2004-01-01	18.1
2004-04-01	18.5
2004-07-01	18.4
2004-10-01	20.2
2005-01-01	20.7
2005-04-01	22.4
2005-07-01	23.6
2005-10-01	23.1
2006-01-01	24.3
2006-04-01	24.9
2006-07-01	25.1
2006-10-01	26.3
2007-01-01	26.9
2007-04-01	27
2007-07-01	27.5
2007-10-01	28.4
2008-01-01	29.6
2008-04-01	29.5
2008-07-01	30.9
2008-10-01	30.3
2009-01-01	30.4
2009-04-01	30.6
2009-07-01	31
2009-10-01	32.3
2010-01-01	33.7
2010-04-01	33.8
2010-07-01	34.4
2010-10-01	32.5
2011-01-01	33.1
2011-04-01	33.3
2011-07-01	33.2
2011-10-01	32.4
2012-01-01	33.3
2012-04-01	34.8
2012-07-01	34.7
2012-10-01	35.2
2013-01-01	35.2
2013-04-01	37
2013-07-01	36.7
2013-10-01	36.6
2014-01-01	35.9
2014-04-01	37.8
2014-07-01	38
2014-10-01	38.2
2015-01-01	38.8
2015-04-01	40.4
2015-07-01	40.5
2015-10-01	41.0
2016-01-01	41.3
2016-04-01	43.3
2016-07-01	43.1
2016-10-01	43.2
2017-01-01	43.3
2017-04-01	43.8
2017-07-01	45.1
2017-10-01	45.5
2018-01-01	46.3
2018-04-01	45.7