Quarter	Millions of US Dollars
1969-01-01	0
1969-04-01	0
1969-07-01	0
1969-10-01	0
1970-01-01	0
1970-04-01	0
1970-07-01	0
1970-10-01	0
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	32
1976-07-01	33
1976-10-01	33
1977-01-01	31
1977-04-01	0
1977-07-01	0
1977-10-01	37
1978-01-01	40
1978-04-01	40
1978-07-01	103
1978-10-01	87
1979-01-01	85
1979-04-01	163
1979-07-01	519
1979-10-01	772
1980-01-01	871
1980-04-01	992
1980-07-01	764
1980-10-01	973
1981-01-01	1141
1981-04-01	1454
1981-07-01	1641
1981-10-01	1508
1982-01-01	1600
1982-04-01	1523
1982-07-01	1887
1982-10-01	2190
1983-01-01	2350
1983-04-01	2462
1983-07-01	2045
1983-10-01	1550
1984-01-01	1782
1984-04-01	2074
1984-07-01	2476
1984-10-01	4230
1985-01-01	3908
1985-04-01	4554
1985-07-01	4808
1985-10-01	4668
1986-01-01	5418
1986-04-01	6330
1986-07-01	7203
1986-10-01	6471
1987-01-01	7622
1987-04-01	6691
1987-07-01	6241
1987-10-01	7564
1988-01-01	7346
1988-04-01	7803
1988-07-01	8440
1988-10-01	8805
1989-01-01	7946
1989-04-01	7531
1989-07-01	7770
1989-10-01	7665
1990-01-01	8879
1990-04-01	9236
1990-07-01	10639
1990-10-01	13102
1991-01-01	14343
1991-04-01	17029
1991-07-01	17175
1991-10-01	15854
1992-01-01	13756
1992-04-01	14077
1992-07-01	13253
1992-10-01	14091
1993-01-01	14526
1993-04-01	12579
1993-07-01	14166
1993-10-01	11707
1994-01-01	10152
1994-04-01	9260
1994-07-01	7753
1994-10-01	8915
1995-01-01	14835
1995-04-01	18663
1995-07-01	21629
1995-10-01	22877
1996-01-01	18178
1996-04-01	16186
1996-07-01	16098
1996-10-01	19326
1997-01-01	21368
1997-04-01	23493
1997-07-01	21137
1997-10-01	21478
1998-01-01	24538
1998-04-01	22899
1998-07-01	26133
1998-10-01	24441
1999-01-01	22525
1999-04-01	28791
1999-07-01	26187
1999-10-01	26324
2000-01-01	26145
2000-04-01	26910
2000-07-01	24820
2000-10-01	26244
2001-01-01	24363
2001-04-01	27723
2001-07-01	31366
2001-10-01	31237
2002-01-01	44906
2002-04-01	38298
2002-07-01	37300
2002-10-01	37199
2003-01-01	29098
2003-04-01	33281
2003-07-01	31024
2003-10-01	34679
2004-01-01	36503
2004-04-01	26065
2004-07-01	31930
2004-10-01	29109
2005-01-01	30549
2005-04-01	35981
2005-07-01	31403
2005-10-01	36297
2006-01-01	41692
2006-04-01	33941
2006-07-01	42692
2006-10-01	38512
2007-01-01	47272
2007-04-01	50530
2007-07-01	53039
2007-10-01	73551
2008-01-01	65317
2008-04-01	70979
2008-07-01	71448
2008-10-01	51294
2009-01-01	55200
2009-04-01	53693
2009-07-01	63255
2009-10-01	62965
2010-01-01	66879
2010-04-01	70679
2010-07-01	79958
2010-10-01	91955
2011-01-01	83533
2011-04-01	99863
2011-07-01	71992
2011-10-01	81999
2012-01-01	89359
2012-04-01	93194
2012-07-01	102021
2012-10-01	92780
2013-01-01	94682
2013-04-01	93222
2013-07-01	107030
2013-10-01	112291
2014-01-01	119270
2014-04-01	131419
2014-07-01	135920
2014-10-01	144195
2015-01-01	136234
2015-04-01	126040
2015-07-01	130097
2015-10-01	128591
2016-01-01	148516
2016-04-01	149587
2016-07-01	141612
2016-10-01	132626
2017-01-01	114612
2017-04-01	118514
2017-07-01	123294
2017-10-01	125435
2018-01-01	130505
2018-04-01	132993