Quarter	Millions of US Dollars
1971-01-01	0
1971-04-01	0
1971-07-01	0
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	17
1978-10-01	62
1979-01-01	61
1979-04-01	60
1979-07-01	96
1979-10-01	108
1980-01-01	95
1980-04-01	106
1980-07-01	146
1980-10-01	85
1981-01-01	78
1981-04-01	100
1981-07-01	27
1981-10-01	27
1982-01-01	60
1982-04-01	49
1982-07-01	70
1982-10-01	75
1983-01-01	70
1983-04-01	162
1983-07-01	137
1983-10-01	133
1984-01-01	106
1984-04-01	0
1984-07-01	20
1984-10-01	197
1985-01-01	414
1985-04-01	416
1985-07-01	411
1985-10-01	463
1986-01-01	568
1986-04-01	644
1986-07-01	779
1986-10-01	842
1987-01-01	838
1987-04-01	826
1987-07-01	1119
1987-10-01	898
1988-01-01	1145
1988-04-01	1059
1988-07-01	636
1988-10-01	743
1989-01-01	300
1989-04-01	271
1989-07-01	667
1989-10-01	554
1990-01-01	540
1990-04-01	549
1990-07-01	224
1990-10-01	512
1991-01-01	532
1991-04-01	956
1991-07-01	956
1991-10-01	962
1992-01-01	958
1992-04-01	828
1992-07-01	794
1992-10-01	930
1993-01-01	1385
1993-04-01	1127
1993-07-01	1603
1993-10-01	1934
1994-01-01	1969
1994-04-01	1924
1994-07-01	1633
1994-10-01	1051
1995-01-01	2066
1995-04-01	2030
1995-07-01	2108
1995-10-01	1847
1996-01-01	1095
1996-04-01	1173
1996-07-01	1021
1996-10-01	2006
1997-01-01	3391
1997-04-01	3263
1997-07-01	3406
1997-10-01	2951
1998-01-01	1915
1998-04-01	2227
1998-07-01	2924
1998-10-01	2493
1999-01-01	3727
1999-04-01	4525
1999-07-01	4996
1999-10-01	5863
2000-01-01	6816
2000-04-01	9065
2000-07-01	5258
2000-10-01	5414
2001-01-01	6107
2001-04-01	4570
2001-07-01	7988
2001-10-01	10872
2002-01-01	13847
2002-04-01	14680
2002-07-01	15208
2002-10-01	18567
2003-01-01	19023
2003-04-01	22616
2003-07-01	21542
2003-10-01	22046
2004-01-01	26769
2004-04-01	26162
2004-07-01	31984
2004-10-01	37289
2005-01-01	44510
2005-04-01	43720
2005-07-01	47533
2005-10-01	49033
2006-01-01	51846
2006-04-01	57218
2006-07-01	66231
2006-10-01	70021
2007-01-01	83241
2007-04-01	82111
2007-07-01	97156
2007-10-01	78441
2008-01-01	90106
2008-04-01	102347
2008-07-01	100163
2008-10-01	108242
2009-01-01	104955
2009-04-01	97222
2009-07-01	133620
2009-10-01	128853
2010-01-01	118475
2010-04-01	111468
2010-07-01	73786
2010-10-01	72201
2011-01-01	44392
2011-04-01	47942
2011-07-01	46709
2011-10-01	48131
2012-01-01	87744
2012-04-01	90103
2012-07-01	75020
2012-10-01	72322
2013-01-01	63426
2013-04-01	56881
2013-07-01	70748
2013-10-01	111053
2014-01-01	101912
2014-04-01	97683
2014-07-01	89130
2014-10-01	53322
2015-01-01	24934
2015-04-01	22622
2015-07-01	15238
2015-10-01	17444
2016-01-01	38367
2016-04-01	41418
2016-07-01	44573
2016-10-01	47548
2017-01-01	29513
2017-04-01	22384
2017-07-01	20515
2017-10-01	13925
2018-01-01	23346
2018-04-01	22840