Quarter	Millions of US Dollars
1977-01-01	0
1977-04-01	0
1977-07-01	0
1977-10-01	0
1978-01-01	0
1978-04-01	0
1978-07-01	0
1978-10-01	0
1979-01-01	0
1979-04-01	0
1979-07-01	0
1979-10-01	0
1980-01-01	0
1980-04-01	0
1980-07-01	0
1980-10-01	0
1981-01-01	0
1981-04-01	61
1981-07-01	63
1981-10-01	70
1982-01-01	174
1982-04-01	109
1982-07-01	109
1982-10-01	109
1983-01-01	0
1983-04-01	79
1983-07-01	76
1983-10-01	73
1984-01-01	77
1984-04-01	0
1984-07-01	0
1984-10-01	24
1985-01-01	223
1985-04-01	224
1985-07-01	603
1985-10-01	1235
1986-01-01	1297
1986-04-01	1487
1986-07-01	1125
1986-10-01	449
1987-01-01	256
1987-04-01	165
1987-07-01	164
1987-10-01	287
1988-01-01	219
1988-04-01	155
1988-07-01	257
1988-10-01	337
1989-01-01	314
1989-04-01	240
1989-07-01	143
1989-10-01	3
1990-01-01	56
1990-04-01	59
1990-07-01	64
1990-10-01	124
1991-01-01	51
1991-04-01	48
1991-07-01	52
1991-10-01	0
1992-01-01	0
1992-04-01	143
1992-07-01	276
1992-10-01	265
1993-01-01	157
1993-04-01	261
1993-07-01	1177
1993-10-01	1415
1994-01-01	1550
1994-04-01	911
1994-07-01	997
1994-10-01	638
1995-01-01	1398
1995-04-01	1315
1995-07-01	1106
1995-10-01	1153
1996-01-01	591
1996-04-01	879
1996-07-01	282
1996-10-01	1028
1997-01-01	1183
1997-04-01	1042
1997-07-01	1074
1997-10-01	1426
1998-01-01	2749
1998-04-01	2776
1998-07-01	4550
1998-10-01	3964
1999-01-01	3644
1999-04-01	3537
1999-07-01	2175
1999-10-01	2141
2000-01-01	577
2000-04-01	1493
2000-07-01	1128
2000-10-01	1742
2001-01-01	2641
2001-04-01	2995
2001-07-01	3334
2001-10-01	2911
2002-01-01	3755
2002-04-01	3081
2002-07-01	2931
2002-10-01	3553
2003-01-01	1398
2003-04-01	2299
2003-07-01	3830
2003-10-01	5393
2004-01-01	7233
2004-04-01	6296
2004-07-01	7163
2004-10-01	5832
2005-01-01	3714
2005-04-01	4086
2005-07-01	4729
2005-10-01	4311
2006-01-01	5830
2006-04-01	5833
2006-07-01	2668
2006-10-01	3371
2007-01-01	3040
2007-04-01	4501
2007-07-01	6102
2007-10-01	5945
2008-01-01	7903
2008-04-01	7455
2008-07-01	5930
2008-10-01	6837
2009-01-01	5481
2009-04-01	5653
2009-07-01	6992
2009-10-01	6203
2010-01-01	6618
2010-04-01	5357
2010-07-01	6506
2010-10-01	4173
2011-01-01	6130
2011-04-01	7276
2011-07-01	10755
2011-10-01	10281
2012-01-01	8666
2012-04-01	13877
2012-07-01	14176
2012-10-01	15010
2013-01-01	14694
2013-04-01	8386
2013-07-01	2102
2013-10-01	2630
2014-01-01	10523
2014-04-01	12179
2014-07-01	13987
2014-10-01	13035
2015-01-01	5020
2015-04-01	3782
2015-07-01	1151
2015-10-01	2513
2016-01-01	8240
2016-04-01	8467
2016-07-01	13900
2016-10-01	11666
2017-01-01	11597
2017-04-01	12894
2017-07-01	13125
2017-10-01	13261
2018-01-01	8023
2018-04-01	6029