Quarter	Percent
1999-01-01	22.4
1999-04-01	23.4
1999-07-01	21.2
1999-10-01	20.9
2000-01-01	21.3
2000-04-01	22.3
2000-07-01	24
2000-10-01	23.4
2001-01-01	24.8
2001-04-01	23.4
2001-07-01	26.7
2001-10-01	27
2002-01-01	25.7
2002-04-01	25.9
2002-07-01	23.9
2002-10-01	22.3
2003-01-01	23.1
2003-04-01	22.7
2003-07-01	22.2
2003-10-01	25.9
2004-01-01	26.6
2004-04-01	30.1
2004-07-01	30.4
2004-10-01	28.9
2005-01-01	28.5
2005-04-01	31.2
2005-07-01	31.8
2005-10-01	31.3
2006-01-01	32.4
2006-04-01	33.6
2006-07-01	32.8
2006-10-01	31.5
2007-01-01	30.9
2007-04-01	34.9
2007-07-01	35.1
2007-10-01	32.9
2008-01-01	31.4
2008-04-01	33.6
2008-07-01	33.4
2008-10-01	32.7
2009-01-01	32.7
2009-04-01	36.4
2009-07-01	37.3
2009-10-01	35.9
2010-01-01	35.2
2010-04-01	35.5
2010-07-01	35.7
2010-10-01	33.8
2011-01-01	30
2011-04-01	30.6
2011-07-01	32.5
2011-10-01	31.7
2012-01-01	31.3
2012-04-01	32.8
2012-07-01	33.2
2012-10-01	34.3
2013-01-01	32
2013-04-01	34.2
2013-07-01	34.2
2013-10-01	33.6
2014-01-01	33
2014-04-01	36.7
2014-07-01	36.3
2014-10-01	35.7
2015-01-01	35.3
2015-04-01	38.2
2015-07-01	37.2
2015-10-01	35.7
2016-01-01	38.2
2016-04-01	39.5
2016-07-01	37.6
2016-10-01	38.9
2017-01-01	40.5
2017-04-01	43.5
2017-07-01	42.8
2017-10-01	44.2
2018-01-01	44.4
2018-04-01	47.6