Quarter	Millions of US Dollars
1975-01-01	64
1975-04-01	135
1976-01-01	49
1976-04-01	20
1976-07-01	22
1976-10-01	29
1977-01-01	183
1977-04-01	248
1977-07-01	176
1977-10-01	293
1978-04-01	352
1979-01-01	180
1979-04-01	776
1979-07-01	55
1979-10-01	419
1980-01-01	466
1980-04-01	932
1980-07-01	635
1980-10-01	655
1981-01-01	285
1981-04-01	200
1981-07-01	58
1981-10-01	253
1982-01-01	733
1982-04-01	-53
1982-07-01	46
1982-10-01	460
1983-01-01	1359
1983-04-01	-415
1983-07-01	75
1983-10-01	1175
1984-01-01	452
1984-04-01	1896
1984-07-01	746
1984-10-01	1364
1985-01-01	-1349
1985-04-01	2452
1985-07-01	-243
1985-10-01	-815
1986-01-01	-24
1986-04-01	-9
1986-07-01	115
1986-10-01	-487
1987-01-01	347
1987-04-01	-591
1987-07-01	-211
1987-10-01	-60
1988-01-01	694
1988-04-01	-1743
1988-07-01	22
1988-10-01	-367
1989-01-01	48
1989-04-01	-370
1989-07-01	-97
1989-10-01	-451
1990-01-01	-73
1990-04-01	-1445
1990-07-01	-303
1990-10-01	-10
1991-01-01	-211
1991-04-01	-197
1991-07-01	-70
1991-10-01	-1009
1992-01-01	-177
1992-04-01	370
1992-07-01	-564
1992-10-01	1269
1993-01-01	3269
1993-04-01	4
1993-07-01	5359
1993-10-01	1804
1994-01-01	3014
1994-04-01	6589
1994-07-01	3995
1994-10-01	1827
1995-01-01	329
1995-04-01	2977
1995-07-01	3036
1995-10-01	-1366
1996-01-01	1288
1996-04-01	5271
1996-07-01	-2846
1996-10-01	-536
1997-01-01	-1398
1997-04-01	1187
1997-07-01	-71
1997-10-01	-3927
1998-01-01	-3157
1998-04-01	1827
1998-07-01	-1808
1998-10-01	-3508
1999-01-01	-5767
1999-04-01	-2735
1999-07-01	-1656
1999-10-01	-1765
2000-01-01	-2179
2000-04-01	-1214
2000-07-01	-2025
2000-10-01	-910
2001-01-01	-1237
2001-04-01	-282
2001-07-01	-1388
2001-10-01	-243
2002-01-01	-103
2002-04-01	810
2002-07-01	-1114
2002-10-01	400
2003-01-01	-1819
2003-04-01	-866
2003-07-01	-164
2003-10-01	-403
2004-01-01	-888
2004-04-01	-263
2004-07-01	-70
2004-10-01	257
2005-01-01	1835
2005-04-01	-542
2005-07-01	-27
2005-10-01	-643
2006-01-01	814
2006-04-01	616
2006-07-01	-139
2006-10-01	317
2007-01-01	-938
2007-04-01	1578
2007-07-01	-1388
2007-10-01	1980
2008-01-01	-3660
2008-04-01	-254
2008-07-01	-808
2008-10-01	-1035
2009-01-01	4759
2009-04-01	8869
2009-07-01	4490
2009-10-01	130
2010-01-01	2684
2010-04-01	-5503
2010-07-01	-96
2010-10-01	7716
2011-01-01	-4723
2011-04-01	-437
2011-07-01	-2085
2011-10-01	4151
2012-01-01	-3401
2012-04-01	2232
2012-07-01	-98
2012-10-01	11353
2013-01-01	10729
2013-04-01	-1897
2013-07-01	3754
2013-10-01	1019
2014-01-01	549
2014-04-01	4524
2014-07-01	2961
2014-10-01	10420
2015-01-01	-4840
2015-04-01	-7873
2015-07-01	2682
2015-10-01	4777
2016-01-01	-7715
2016-04-01	-4371
2016-07-01	1700
2016-10-01	2885
2017-01-01	-830
2017-04-01	-2553
2017-07-01	1020
2017-10-01	-2151
2018-01-01	2836
2018-04-01	-2462