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	863
1984-01-01	921
1984-04-01	762
1984-07-01	562
1984-10-01	1406
1985-01-01	1470
1985-04-01	1801
1985-07-01	1970
1985-10-01	1540
1986-01-01	1852
1986-04-01	1676
1986-07-01	1825
1986-10-01	1716
1987-01-01	1540
1987-04-01	1923
1987-07-01	2509
1987-10-01	2908
1988-01-01	2964
1988-04-01	2329
1988-07-01	1656
1988-10-01	1564
1989-01-01	1360
1989-04-01	1639
1989-07-01	1658
1989-10-01	1378
1990-01-01	2148
1990-04-01	1811
1990-07-01	1596
1990-10-01	1537
1991-01-01	602
1991-04-01	873
1991-07-01	1203
1991-10-01	1712
1992-01-01	2483
1992-04-01	2278
1992-07-01	2836
1992-10-01	3244
1993-01-01	2560
1993-04-01	3107
1993-07-01	11851
1993-10-01	12289
1994-01-01	15121
1994-04-01	15271
1994-07-01	16373
1994-10-01	15628
1995-01-01	11464
1995-04-01	13183
1995-07-01	16717
1995-10-01	19301
1996-01-01	19898
1996-04-01	19549
1996-07-01	23740
1996-10-01	26792
1997-01-01	26292
1997-04-01	27431
1997-07-01	22785
1997-10-01	41520
1998-01-01	44988
1998-04-01	43895
1998-07-01	39312
1998-10-01	16486
1999-01-01	13195
1999-04-01	21216
1999-07-01	25040
1999-10-01	27462
2000-01-01	30487
2000-04-01	63444
2000-07-01	63735
2000-10-01	68463
2001-01-01	68587
2001-04-01	32853
2001-07-01	32292
2001-10-01	25145
2002-01-01	34720
2002-04-01	40872
2002-07-01	43736
2002-10-01	45901
2003-01-01	40290
2003-04-01	39932
2003-07-01	40277
2003-10-01	39999
2004-01-01	36713
2004-04-01	71361
2004-07-01	74786
2004-10-01	75083
2005-01-01	76893
2005-04-01	46463
2005-07-01	38625
2005-10-01	37564
2006-01-01	37295
2006-04-01	22526
2006-07-01	26414
2006-10-01	25482
2007-01-01	26839
2007-04-01	29746
2007-07-01	26096
2007-10-01	36092
2008-01-01	33095
2008-04-01	35338
2008-07-01	33637
2008-10-01	24579
2009-01-01	26815
2009-04-01	21554
2009-07-01	23141
2009-10-01	23683
2010-01-01	22523
2010-04-01	21280
2010-07-01	25769
2010-10-01	21265
2011-01-01	23484
2011-04-01	24226
2011-07-01	17714
2011-10-01	19377
2012-01-01	17787
2012-04-01	18031
2012-07-01	23557
2012-10-01	28473
2013-01-01	34242
2013-04-01	36339
2013-07-01	32510
2013-10-01	38619
2014-01-01	43353
2014-04-01	43440
2014-07-01	46319
2014-10-01	39437
2015-01-01	34413
2015-04-01	34006
2015-07-01	39118
2015-10-01	38492
2016-01-01	41692
2016-04-01	67623
2016-07-01	59210
2016-10-01	67652
2017-01-01	63467
2017-04-01	45538
2017-07-01	47038
2017-10-01	35461
2018-01-01	32364
2018-04-01	35438