Quarter	Millions of US Dollars
1971-10-01	0
1972-01-01	0
1972-04-01	0
1972-07-01	0
1972-10-01	0
1973-01-01	0
1973-04-01	0
1973-07-01	0
1973-10-01	0
1974-01-01	0
1974-04-01	0
1974-07-01	0
1974-10-01	0
1975-01-01	0
1975-04-01	0
1975-07-01	0
1975-10-01	0
1976-01-01	0
1976-04-01	0
1976-07-01	0
1976-10-01	0
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	34
1979-01-01	160
1979-04-01	161
1979-07-01	164
1979-10-01	145
1980-01-01	64
1980-04-01	177
1980-07-01	261
1980-10-01	278
1981-01-01	303
1981-04-01	664
1981-07-01	861
1981-10-01	957
1982-01-01	1299
1982-04-01	943
1982-07-01	771
1982-10-01	932
1983-01-01	639
1983-04-01	732
1983-07-01	990
1983-10-01	913
1984-01-01	971
1984-04-01	812
1984-07-01	612
1984-10-01	1407
1985-01-01	1471
1985-04-01	1803
1985-07-01	1972
1985-10-01	1499
1986-01-01	1811
1986-04-01	1599
1986-07-01	1749
1986-10-01	1680
1987-01-01	1504
1987-04-01	2023
1987-07-01	2609
1987-10-01	3008
1988-01-01	3064
1988-04-01	2297
1988-07-01	1624
1988-10-01	1532
1989-01-01	1328
1989-04-01	1599
1989-07-01	1618
1989-10-01	1338
1990-01-01	2173
1990-04-01	1876
1990-07-01	1661
1990-10-01	1702
1991-01-01	827
1991-04-01	1120
1991-07-01	1694
1991-10-01	2114
1992-01-01	2617
1992-04-01	2397
1992-07-01	2841
1992-10-01	3360
1993-01-01	2779
1993-04-01	3262
1993-07-01	11837
1993-10-01	12124
1994-01-01	14593
1994-04-01	15945
1994-07-01	17592
1994-10-01	16521
1995-01-01	12789
1995-04-01	15534
1995-07-01	19264
1995-10-01	21851
1996-01-01	22997
1996-04-01	25677
1996-07-01	26009
1996-10-01	30207
1997-01-01	29904
1997-04-01	29975
1997-07-01	26668
1997-10-01	45034
1998-01-01	48150
1998-04-01	46744
1998-07-01	41739
1998-10-01	16637
1999-01-01	14113
1999-04-01	23451
1999-07-01	27309
1999-10-01	30321
2000-01-01	35145
2000-04-01	64442
2000-07-01	65628
2000-10-01	71416
2001-01-01	71436
2001-04-01	36346
2001-07-01	35102
2001-10-01	26259
2002-01-01	35217
2002-04-01	41330
2002-07-01	44500
2002-10-01	48071
2003-01-01	43805
2003-04-01	43770
2003-07-01	43351
2003-10-01	43131
2004-01-01	39681
2004-04-01	75726
2004-07-01	76788
2004-10-01	77622
2005-01-01	78775
2005-04-01	46515
2005-07-01	40910
2005-10-01	39786
2006-01-01	40509
2006-04-01	26954
2006-07-01	32840
2006-10-01	33365
2007-01-01	38710
2007-04-01	40628
2007-07-01	31228
2007-10-01	41646
2008-01-01	40612
2008-04-01	42875
2008-07-01	39961
2008-10-01	29792
2009-01-01	29264
2009-04-01	28890
2009-07-01	32846
2009-10-01	36525
2010-01-01	35367
2010-04-01	29807
2010-07-01	35685
2010-10-01	28604
2011-01-01	30114
2011-04-01	31466
2011-07-01	24367
2011-10-01	28184
2012-01-01	29180
2012-04-01	32455
2012-07-01	39317
2012-10-01	42993
2013-01-01	49085
2013-04-01	52789
2013-07-01	48990
2013-10-01	56964
2014-01-01	66309
2014-04-01	68013
2014-07-01	67011
2014-10-01	58091
2015-01-01	49788
2015-04-01	49456
2015-07-01	56538
2015-10-01	54966
2016-01-01	61414
2016-04-01	89875
2016-07-01	79465
2016-10-01	91116
2017-01-01	91638
2017-04-01	76825
2017-07-01	79598
2017-10-01	64740
2018-01-01	54113
2018-04-01	46863