Quarter	Millions of US Dollars
1966-01-01	15
1966-04-01	15
1966-07-01	15
1966-10-01	15
1967-01-01	15
1967-04-01	15
1967-07-01	15
1967-10-01	15
1968-01-01	15
1968-04-01	15
1968-07-01	15
1968-10-01	15
1969-01-01	15
1969-04-01	15
1969-07-01	15
1969-10-01	15
1970-01-01	15
1970-04-01	15
1970-07-01	15
1970-10-01	15
1971-01-01	15
1971-04-01	15
1971-07-01	15
1971-10-01	15
1972-01-01	65
1972-04-01	81
1972-07-01	80
1972-10-01	79
1973-01-01	87
1973-04-01	97
1973-07-01	98
1973-10-01	89
1974-01-01	93
1974-04-01	92
1974-07-01	125
1974-10-01	220
1975-01-01	257
1975-04-01	302
1975-07-01	553
1975-10-01	595
1976-01-01	603
1976-04-01	754
1976-07-01	844
1976-10-01	994
1977-01-01	1013
1977-04-01	1236
1977-07-01	1404
1977-10-01	1635
1978-01-01	1992
1978-04-01	2029
1978-07-01	2232
1978-10-01	2522
1979-01-01	2538
1979-04-01	2706
1979-07-01	2953
1979-10-01	2915
1980-01-01	2630
1980-04-01	2991
1980-07-01	2932
1980-10-01	2773
1981-01-01	2704
1981-04-01	2611
1981-07-01	2661
1981-10-01	2923
1982-01-01	3131
1982-04-01	3223
1982-07-01	3176
1982-10-01	3524
1983-01-01	3649
1983-04-01	3484
1983-07-01	3409
1983-10-01	3348
1984-01-01	3509
1984-04-01	3430
1984-07-01	3329
1984-10-01	3719
1985-01-01	3766
1985-04-01	3937
1985-07-01	4922
1985-10-01	5217
1986-01-01	5873
1986-04-01	6576
1986-07-01	7872
1986-10-01	8655
1987-01-01	9420
1987-04-01	9601
1987-07-01	9301
1987-10-01	10031
1988-01-01	9556
1988-04-01	9953
1988-07-01	9726
1988-10-01	10151
1989-01-01	9280
1989-04-01	8949
1989-07-01	8970
1989-10-01	9338
1990-01-01	9002
1990-04-01	9464
1990-07-01	9841
1990-10-01	9866
1991-01-01	9339
1991-04-01	9182
1991-07-01	9303
1991-10-01	8926
1992-01-01	8570
1992-04-01	7972
1992-07-01	7866
1992-10-01	7129
1993-01-01	6477
1993-04-01	6039
1993-07-01	8074
1993-10-01	7853
1994-01-01	8217
1994-04-01	8130
1994-07-01	7897
1994-10-01	7815
1995-01-01	7793
1995-04-01	6983
1995-07-01	6611
1995-10-01	6116
1996-01-01	5594
1996-04-01	5527
1996-07-01	5205
1996-10-01	4776
1997-01-01	3667
1997-04-01	3582
1997-07-01	3589
1997-10-01	3891
1998-01-01	3643
1998-04-01	3627
1998-07-01	3447
1998-10-01	3635
1999-01-01	3278
1999-04-01	3254
1999-07-01	3321
1999-10-01	3146
2000-01-01	3239
2000-04-01	3094
2000-07-01	2871
2000-10-01	2879
2001-01-01	2386
2001-04-01	2414
2001-07-01	2464
2001-10-01	2386
2002-01-01	2294
2002-04-01	2378
2002-07-01	2311
2002-10-01	2364
2003-01-01	2298
2003-04-01	2715
2003-07-01	2673
2003-10-01	2853
2004-01-01	2434
2004-04-01	2446
2004-07-01	2532
2004-10-01	2544
2005-01-01	2132
2005-04-01	1991
2005-07-01	1786
2005-10-01	1652
2006-01-01	1482
2006-04-01	1508
2006-07-01	1499
2006-10-01	1248
2007-01-01	1236
2007-04-01	1251
2007-07-01	1289
2007-10-01	1293
2008-01-01	1162
2008-04-01	749
2008-07-01	849
2008-10-01	778
2009-01-01	860
2009-04-01	867
2009-07-01	781
2009-10-01	774
2010-01-01	771
2010-04-01	783
2010-07-01	798
2010-10-01	803
2011-01-01	699
2011-04-01	806
2011-07-01	818
2011-10-01	816
2012-01-01	856
2012-04-01	591
2012-07-01	541
2012-10-01	1328
2013-01-01	2371
2013-04-01	676
2013-07-01	902
2013-10-01	898
2014-01-01	1359
2014-04-01	1351
2014-07-01	1272
2014-10-01	1214
2015-01-01	1172
2015-04-01	1503
2015-07-01	1533
2015-10-01	1238
2016-01-01	1282
2016-04-01	1105
2016-07-01	1146
2016-10-01	1203
2017-01-01	1769
2017-04-01	1905
2017-07-01	2044
2017-10-01	2645
2018-01-01	2696
2018-04-01	2570