Quarter	Millions of US Dollars
1972-01-01	40
1972-04-01	80
1972-07-01	80
1972-10-01	115
1973-01-01	150
1973-04-01	156
1973-07-01	194
1973-10-01	218
1974-01-01	221
1974-04-01	219
1974-07-01	216
1974-10-01	220
1975-01-01	297
1975-04-01	339
1975-07-01	328
1975-10-01	329
1976-01-01	382
1976-04-01	454
1976-07-01	463
1976-10-01	465
1977-01-01	468
1977-04-01	606
1977-07-01	610
1977-10-01	720
1978-01-01	1002
1978-04-01	1010
1978-07-01	1081
1978-10-01	1090
1979-01-01	1056
1979-04-01	1056
1979-07-01	1085
1979-10-01	1071
1980-01-01	922
1980-04-01	1040
1980-07-01	1031
1980-10-01	997
1981-01-01	901
1981-04-01	934
1981-07-01	1033
1981-10-01	1217
1982-01-01	1335
1982-04-01	1174
1982-07-01	1326
1982-10-01	1376
1983-01-01	1207
1983-04-01	1157
1983-07-01	1150
1983-10-01	1142
1984-01-01	1158
1984-04-01	1091
1984-07-01	1064
1984-10-01	1049
1985-01-01	991
1985-04-01	980
1985-07-01	979
1985-10-01	886
1986-01-01	908
1986-04-01	885
1986-07-01	895
1986-10-01	797
1987-01-01	744
1987-04-01	703
1987-07-01	704
1987-10-01	616
1988-01-01	604
1988-04-01	490
1988-07-01	312
1988-10-01	265
1989-01-01	259
1989-04-01	252
1989-07-01	256
1989-10-01	255
1990-01-01	34652
1990-04-01	34743
1990-07-01	35073
1990-10-01	35254
1991-01-01	34793
1991-04-01	34548
1991-07-01	35035
1991-10-01	35665
1992-01-01	35239
1992-04-01	35657
1992-07-01	36164
1992-10-01	35359
1993-01-01	35522
1993-04-01	35422
1993-07-01	36050
1993-10-01	35747
1994-01-01	36022
1994-04-01	36198
1994-07-01	36813
1994-10-01	36447
1995-01-01	36419
1995-04-01	36944
1995-07-01	38706
1995-10-01	39753
1996-01-01	42872
1996-04-01	42976
1996-07-01	50453
1996-10-01	50869
1997-01-01	52304
1997-04-01	54983
1997-07-01	48892
1997-10-01	49158
1998-01-01	49600
1998-04-01	49708
1998-07-01	50201
1998-10-01	50553
1999-01-01	50541
1999-04-01	52778
1999-07-01	54054
1999-10-01	54784
2000-01-01	56114
2000-04-01	55446
2000-07-01	56169
2000-10-01	55020
2001-01-01	58568
2001-04-01	54313
2001-07-01	55987
2001-10-01	50182
2002-01-01	51220
2002-04-01	48827
2002-07-01	49384
2002-10-01	50751
2003-01-01	43853
2003-04-01	42018
2003-07-01	39435
2003-10-01	40880
2004-01-01	42115
2004-04-01	42959
2004-07-01	43370
2004-10-01	44678
2005-01-01	45197
2005-04-01	44237
2005-07-01	44169
2005-10-01	43655
2006-01-01	44137
2006-04-01	43748
2006-07-01	42400
2006-10-01	42457
2007-01-01	40511
2007-04-01	40642
2007-07-01	42062
2007-10-01	42097
2008-01-01	42112
2008-04-01	41778
2008-07-01	40274
2008-10-01	40702
2009-01-01	39403
2009-04-01	39425
2009-07-01	41406
2009-10-01	42921
2010-01-01	39849
2010-04-01	40573
2010-07-01	42310
2010-10-01	45084
2011-01-01	44823
2011-04-01	46044
2011-07-01	46818
2011-10-01	46562
2012-01-01	49277
2012-04-01	49813
2012-07-01	50088
2012-10-01	49702
2013-01-01	48873
2013-04-01	49403
2013-07-01	50505
2013-10-01	54214
2014-01-01	56660
2014-04-01	57925
2014-07-01	56274
2014-10-01	57554
2015-01-01	61866
2015-04-01	62914
2015-07-01	62817
2015-10-01	62484
2016-01-01	68232
2016-04-01	69478
2016-07-01	67337
2016-10-01	67130
2017-01-01	70361
2017-04-01	68226
2017-07-01	68752
2017-10-01	67880
2018-01-01	73688
2018-04-01	73660