Quarter	Millions of US Dollars
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	0
1979-01-01	0
1979-04-01	0
1979-07-01	0
1979-10-01	16
1980-01-01	14
1980-04-01	16
1980-07-01	15
1980-10-01	0
1981-01-01	20
1981-04-01	95
1981-07-01	136
1981-10-01	178
1982-01-01	186
1982-04-01	135
1982-07-01	141
1982-10-01	251
1983-01-01	217
1983-04-01	226
1983-07-01	283
1983-10-01	142
1984-01-01	146
1984-04-01	128
1984-07-01	56
1984-10-01	198
1985-01-01	200
1985-04-01	177
1985-07-01	155
1985-10-01	202
1986-01-01	333
1986-04-01	436
1986-07-01	442
1986-10-01	405
1987-01-01	319
1987-04-01	459
1987-07-01	844
1987-10-01	972
1988-01-01	937
1988-04-01	794
1988-07-01	487
1988-10-01	310
1989-01-01	386
1989-04-01	266
1989-07-01	185
1989-10-01	91
1990-01-01	940
1990-04-01	940
1990-07-01	940
1990-10-01	1088
1991-01-01	204
1991-04-01	435
1991-07-01	475
1991-10-01	499
1992-01-01	665
1992-04-01	439
1992-07-01	904
1992-10-01	910
1993-01-01	680
1993-04-01	768
1993-07-01	1941
1993-10-01	1909
1994-01-01	3243
1994-04-01	3147
1994-07-01	3097
1994-10-01	2474
1995-01-01	1411
1995-04-01	2000
1995-07-01	3708
1995-10-01	3888
1996-01-01	3614
1996-04-01	3056
1996-07-01	1673
1996-10-01	2525
1997-01-01	3074
1997-04-01	3767
1997-07-01	3984
1997-10-01	3298
1998-01-01	3415
1998-04-01	2468
1998-07-01	1888
1998-10-01	2577
1999-01-01	1867
1999-04-01	1961
1999-07-01	2137
1999-10-01	1686
2000-01-01	1959
2000-04-01	2494
2000-07-01	2312
2000-10-01	2070
2001-01-01	2906
2001-04-01	4073
2001-07-01	4482
2001-10-01	4420
2002-01-01	3824
2002-04-01	3526
2002-07-01	3251
2002-10-01	3673
2003-01-01	3981
2003-04-01	5244
2003-07-01	4465
2003-10-01	5334
2004-01-01	5696
2004-04-01	3691
2004-07-01	3618
2004-10-01	2253
2005-01-01	1193
2005-04-01	836
2005-07-01	1297
2005-10-01	1597
2006-01-01	1935
2006-04-01	2408
2006-07-01	2778
2006-10-01	2659
2007-01-01	2604
2007-04-01	2822
2007-07-01	2463
2007-10-01	4425
2008-01-01	5529
2008-04-01	4440
2008-07-01	4681
2008-10-01	2708
2009-01-01	2258
2009-04-01	1950
2009-07-01	1392
2009-10-01	2298
2010-01-01	3937
2010-04-01	3450
2010-07-01	3435
2010-10-01	483
2011-01-01	840
2011-04-01	2804
2011-07-01	2354
2011-10-01	2972
2012-01-01	1469
2012-04-01	839
2012-07-01	4616
2012-10-01	4389
2013-01-01	5699
2013-04-01	7191
2013-07-01	5116
2013-10-01	6225
2014-01-01	10283
2014-04-01	10040
2014-07-01	9656
2014-10-01	8158
2015-01-01	4352
2015-04-01	3372
2015-07-01	6434
2015-10-01	9099
2016-01-01	10362
2016-04-01	11890
2016-07-01	8539
2016-10-01	8933
2017-01-01	8284
2017-04-01	9575
2017-07-01	11660
2017-10-01	9067
2018-01-01	8274
2018-04-01	8246