Quarter	Percent
1987-12-31	58.1
1988-03-31	119.7
1988-06-30	128.8
1988-09-30	81.3
1988-12-31	76.9
1989-03-31	26.4
1989-06-30	32.5
1989-09-30	21.7
1989-12-31	16.1
1990-03-31	20.4
1990-06-30	10.6
1990-09-30	8.5
1990-12-31	-19.9
1991-03-31	-25.9
1991-06-30	-30.3
1991-09-30	-19.8
1991-12-31	8.7
1992-03-31	19.7
1992-06-30	29.1
1992-09-30	24
1992-12-31	24.9
1993-03-31	21.7
1993-06-30	19.2
1993-09-30	16.3
1993-12-31	16.9
1994-03-31	11.2
1994-06-30	9.8
1994-09-30	5.3
1994-12-31	1
1995-03-31	1.5
1995-06-30	1.9
1995-09-30	14.4
1995-12-31	-4.5
1996-03-31	-5.2
1996-06-30	-7
1996-09-30	-19.8
1996-12-31	-6.1
1997-03-31	-10
1997-06-30	-0.1
1997-09-30	-18.8
1997-12-31	1.7
1998-03-31	-11.3
1998-06-30	-11.9
1998-09-30	13.3
1998-12-31	-8.5
1999-03-31	10.1
1999-06-30	20.6
1999-09-30	8.1
1999-12-31	9.3
2000-03-31	22.5
2000-06-30	8.7
2000-09-30	37.3
2000-12-31	47.9
2001-03-31	37.7
2001-06-30	46.7
2001-09-30	25.9
2001-12-31	17.8
2002-03-31	14.7
2002-06-30	10
2002-09-30	10.3
2002-12-31	11.2
2003-03-31	7.7
2003-06-30	0.6
2003-09-30	10.1
2003-12-31	4.7
2004-03-31	5.1
2004-06-30	4.1
2004-09-30	26.5
2004-12-31	26.8
2005-03-31	35.1
2005-06-30	31.2
2005-09-30	0.7
2005-12-31	14
2006-03-31	4.2
2006-06-30	12.5
2006-09-30	13.3
2006-12-31	2.3
2007-03-31	5.2
2007-06-30	1.8
2007-09-30	-2
2007-12-31	18.5
2008-03-31	34.1
2008-06-30	42.8
2008-09-30	49.6
2008-12-31	16.7
2009-03-31	7.6
2009-06-30	-7.4
2009-09-30	-14.7
2009-12-31	-15
2010-03-31	-12.9
2010-06-30	-10.9
2010-09-30	-4.8
2010-12-31	7
2011-03-31	-3.5
2011-06-30	2.5
2011-09-30	-2.2
2011-12-31	-10.6
2012-03-31	-18.4
2012-06-30	-23.5
2012-09-30	-14.6
2012-12-31	3.3
2013-03-31	40.7
2013-06-30	11
2013-09-30	34.8
2013-12-31	15.1
2014-03-31	-13.5
2014-06-30	7.5
2014-09-30	-23.2
2014-12-31	-48.4
2015-03-31	-42.8
2015-06-30	-36.9
2015-09-30	-28.8
2015-12-31	8.3
2016-03-31	19.6
2016-06-30	-8.9
2016-09-30	-7.5
2016-12-31	0.1
2017-03-31	-16.4
2017-06-30	14.2
2017-09-30	15.4
2017-12-31	-16.9
2018-03-31	-8
2018-06-30	-17.3
2018-09-30	11.6
2018-12-31	3.5
2019-03-31	1.8
2019-06-30	2.3
2019-09-30	-27.6
2019-12-31	-4.5