Quarter	Millions of US Dollars
1971-10-01	15
1972-01-01	15
1972-04-01	47
1972-07-01	64
1972-10-01	64
1973-01-01	70
1973-04-01	78
1973-07-01	78
1973-10-01	71
1974-01-01	75
1974-04-01	75
1974-07-01	73
1974-10-01	101
1975-01-01	111
1975-04-01	111
1975-07-01	139
1975-10-01	147
1976-01-01	149
1976-04-01	148
1976-07-01	186
1976-10-01	307
1977-01-01	306
1977-04-01	360
1977-07-01	399
1977-10-01	557
1978-01-01	792
1978-04-01	978
1978-07-01	1152
1978-10-01	1351
1979-01-01	1587
1979-04-01	1685
1979-07-01	1748
1979-10-01	1891
1980-01-01	1836
1980-04-01	2064
1980-07-01	2092
1980-10-01	2036
1981-01-01	1948
1981-04-01	2048
1981-07-01	2051
1981-10-01	2247
1982-01-01	2163
1982-04-01	2236
1982-07-01	2357
1982-10-01	2541
1983-01-01	2619
1983-04-01	2779
1983-07-01	2886
1983-10-01	2875
1984-01-01	2966
1984-04-01	2891
1984-07-01	2894
1984-10-01	2871
1985-01-01	2962
1985-04-01	3153
1985-07-01	3485
1985-10-01	3413
1986-01-01	3632
1986-04-01	3919
1986-07-01	4180
1986-10-01	4109
1987-01-01	4797
1987-04-01	4741
1987-07-01	4503
1987-10-01	5551
1988-01-01	5330
1988-04-01	5524
1988-07-01	5109
1988-10-01	5267
1989-01-01	5088
1989-04-01	4786
1989-07-01	4881
1989-10-01	4944
1990-01-01	4875
1990-04-01	4804
1990-07-01	5214
1990-10-01	5902
1991-01-01	6578
1991-04-01	6290
1991-07-01	7285
1991-10-01	9557
1992-01-01	11023
1992-04-01	15684
1992-07-01	18641
1992-10-01	20292
1993-01-01	24410
1993-04-01	26382
1993-07-01	26494
1993-10-01	25647
1994-01-01	28037
1994-04-01	31709
1994-07-01	35838
1994-10-01	35827
1995-01-01	40231
1995-04-01	40259
1995-07-01	38545
1995-10-01	37335
1996-01-01	37990
1996-04-01	36783
1996-07-01	36400
1996-10-01	36389
1997-01-01	34486
1997-04-01	33755
1997-07-01	32177
1997-10-01	28150
1998-01-01	26313
1998-04-01	27410
1998-07-01	28562
1998-10-01	27479
1999-01-01	25525
1999-04-01	24803
1999-07-01	25894
1999-10-01	24686
2000-01-01	22193
2000-04-01	21865
2000-07-01	19796
2000-10-01	18827
2001-01-01	16731
2001-04-01	20338
2001-07-01	21126
2001-10-01	19938
2002-01-01	20638
2002-04-01	21343
2002-07-01	20544
2002-10-01	21283
2003-01-01	28515
2003-04-01	33046
2003-07-01	32945
2003-10-01	33686
2004-01-01	34170
2004-04-01	32858
2004-07-01	31341
2004-10-01	33856
2005-01-01	32437
2005-04-01	29501
2005-07-01	29383
2005-10-01	28864
2006-01-01	28480
2006-04-01	29689
2006-07-01	21457
2006-10-01	22540
2007-01-01	20624
2007-04-01	20165
2007-07-01	14128
2007-10-01	14084
2008-01-01	14909
2008-04-01	14675
2008-07-01	6331
2008-10-01	5741
2009-01-01	7946
2009-04-01	3712
2009-07-01	3858
2009-10-01	3853
2010-01-01	5393
2010-04-01	6219
2010-07-01	6496
2010-10-01	8468
2011-01-01	19621
2011-04-01	17530
2011-07-01	17667
2011-10-01	17376
2012-01-01	18895
2012-04-01	21366
2012-07-01	19771
2012-10-01	19907
2013-01-01	19872
2013-04-01	18934
2013-07-01	19804
2013-10-01	23006
2014-01-01	22677
2014-04-01	25283
2014-07-01	25824
2014-10-01	25774
2015-01-01	24576
2015-04-01	28038
2015-07-01	27627
2015-10-01	23863
2016-01-01	18883
2016-04-01	22706
2016-07-01	22447
2016-10-01	21771
2017-01-01	20707
2017-04-01	21956
2017-07-01	24499
2017-10-01	24244
2018-01-01	23884
2018-04-01	20443