Quarter	Millions of US Dollars
1971-01-01	15
1971-04-01	15
1971-07-01	15
1971-10-01	15
1972-01-01	15
1972-04-01	15
1972-07-01	24
1972-10-01	24
1973-01-01	50
1973-04-01	54
1973-07-01	53
1973-10-01	50
1974-01-01	53
1974-04-01	53
1974-07-01	62
1974-10-01	69
1975-01-01	112
1975-04-01	194
1975-07-01	228
1975-10-01	402
1976-01-01	561
1976-04-01	613
1976-07-01	721
1976-10-01	842
1977-01-01	1014
1977-04-01	1146
1977-07-01	1188
1977-10-01	1414
1978-01-01	1555
1978-04-01	1561
1978-07-01	1737
1978-10-01	1832
1979-01-01	1878
1979-04-01	1890
1979-07-01	2084
1979-10-01	2084
1980-01-01	1904
1980-04-01	2038
1980-07-01	1985
1980-10-01	1873
1981-01-01	1791
1981-04-01	1674
1981-07-01	1746
1981-10-01	1783
1982-01-01	1704
1982-04-01	1755
1982-07-01	1765
1982-10-01	1888
1983-01-01	1973
1983-04-01	1935
1983-07-01	1905
1983-10-01	1830
1984-01-01	1898
1984-04-01	1880
1984-07-01	1848
1984-10-01	1815
1985-01-01	1856
1985-04-01	1807
1985-07-01	2282
1985-10-01	2275
1986-01-01	2528
1986-04-01	2955
1986-07-01	3292
1986-10-01	3280
1987-01-01	4007
1987-04-01	4095
1987-07-01	4028
1987-10-01	4396
1988-01-01	4845
1988-04-01	4985
1988-07-01	5207
1988-10-01	5402
1989-01-01	5455
1989-04-01	5192
1989-07-01	5211
1989-10-01	5465
1990-01-01	5481
1990-04-01	5561
1990-07-01	5311
1990-10-01	5255
1991-01-01	4634
1991-04-01	4441
1991-07-01	4792
1991-10-01	5065
1992-01-01	4534
1992-04-01	5081
1992-07-01	4942
1992-10-01	4485
1993-01-01	4434
1993-04-01	3960
1993-07-01	3895
1993-10-01	3719
1994-01-01	3441
1994-04-01	3529
1994-07-01	3796
1994-10-01	3971
1995-01-01	3845
1995-04-01	3663
1995-07-01	3561
1995-10-01	3445
1996-01-01	3353
1996-04-01	3917
1996-07-01	4142
1996-10-01	4965
1997-01-01	5311
1997-04-01	5266
1997-07-01	6378
1997-10-01	6590
1998-01-01	6820
1998-04-01	8449
1998-07-01	8768
1998-10-01	10686
1999-01-01	11896
1999-04-01	12238
1999-07-01	12744
1999-10-01	13058
2000-01-01	13482
2000-04-01	14500
2000-07-01	15776
2000-10-01	15640
2001-01-01	14039
2001-04-01	13950
2001-07-01	13123
2001-10-01	13500
2002-01-01	14013
2002-04-01	14910
2002-07-01	14657
2002-10-01	15854
2003-01-01	15762
2003-04-01	15832
2003-07-01	16096
2003-10-01	16813
2004-01-01	16883
2004-04-01	17127
2004-07-01	16964
2004-10-01	18053
2005-01-01	17314
2005-04-01	16989
2005-07-01	16851
2005-10-01	16558
2006-01-01	16305
2006-04-01	16447
2006-07-01	18703
2006-10-01	18616
2007-01-01	18609
2007-04-01	19786
2007-07-01	20438
2007-10-01	20560
2008-01-01	21428
2008-04-01	21509
2008-07-01	20181
2008-10-01	19395
2009-01-01	22169
2009-04-01	27091
2009-07-01	28257
2009-10-01	28681
2010-01-01	27958
2010-04-01	26123
2010-07-01	29607
2010-10-01	29676
2011-01-01	31002
2011-04-01	31576
2011-07-01	30536
2011-10-01	31310
2012-01-01	32084
2012-04-01	33575
2012-07-01	35529
2012-10-01	38987
2013-01-01	37187
2013-04-01	42291
2013-07-01	46739
2013-10-01	51766
2014-01-01	52147
2014-04-01	51488
2014-07-01	49732
2014-10-01	49612
2015-01-01	51634
2015-04-01	52349
2015-07-01	52092
2015-10-01	50410
2016-01-01	51389
2016-04-01	51111
2016-07-01	51970
2016-10-01	51077
2017-01-01	52467
2017-04-01	52841
2017-07-01	50541
2017-10-01	47411
2018-01-01	47244
2018-04-01	45952