Quarter	Millions of US Dollars
1972-01-01	19
1972-04-01	54
1972-07-01	54
1972-10-01	54
1973-01-01	55
1973-04-01	58
1973-07-01	59
1973-10-01	56
1974-01-01	57
1974-04-01	74
1974-07-01	104
1974-10-01	109
1975-01-01	180
1975-04-01	281
1975-07-01	274
1975-10-01	275
1976-01-01	292
1976-04-01	302
1976-07-01	387
1976-10-01	470
1977-01-01	537
1977-04-01	625
1977-07-01	762
1977-10-01	788
1978-01-01	802
1978-04-01	800
1978-07-01	834
1978-10-01	833
1979-01-01	794
1979-04-01	867
1979-07-01	894
1979-10-01	920
1980-01-01	892
1980-04-01	896
1980-07-01	973
1980-10-01	961
1981-01-01	950
1981-04-01	961
1981-07-01	965
1981-10-01	1130
1982-01-01	1164
1982-04-01	1133
1982-07-01	1198
1982-10-01	1269
1983-01-01	1410
1983-04-01	1417
1983-07-01	1411
1983-10-01	1608
1984-01-01	1765
1984-04-01	1797
1984-07-01	1833
1984-10-01	1875
1985-01-01	1910
1985-04-01	2066
1985-07-01	2567
1985-10-01	2696
1986-01-01	2920
1986-04-01	2955
1986-07-01	3167
1986-10-01	3128
1987-01-01	3469
1987-04-01	3524
1987-07-01	3835
1987-10-01	4341
1988-01-01	4378
1988-04-01	4303
1988-07-01	4363
1988-10-01	5188
1989-01-01	5016
1989-04-01	5312
1989-07-01	5392
1989-10-01	5325
1990-01-01	5161
1990-04-01	5202
1990-07-01	5636
1990-10-01	5937
1991-01-01	5770
1991-04-01	6167
1991-07-01	6507
1991-10-01	6659
1992-01-01	6396
1992-04-01	6835
1992-07-01	6497
1992-10-01	5862
1993-01-01	5866
1993-04-01	5804
1993-07-01	9262
1993-10-01	9622
1994-01-01	10213
1994-04-01	9484
1994-07-01	9415
1994-10-01	8831
1995-01-01	9342
1995-04-01	9175
1995-07-01	9224
1995-10-01	9958
1996-01-01	10147
1996-04-01	9345
1996-07-01	8811
1996-10-01	10427
1997-01-01	10394
1997-04-01	10612
1997-07-01	10788
1997-10-01	10277
1998-01-01	11202
1998-04-01	12300
1998-07-01	11868
1998-10-01	11771
1999-01-01	12515
1999-04-01	12074
1999-07-01	12165
1999-10-01	11410
2000-01-01	10873
2000-04-01	11312
2000-07-01	11352
2000-10-01	11433
2001-01-01	11251
2001-04-01	12565
2001-07-01	12843
2001-10-01	12389
2002-01-01	12301
2002-04-01	14092
2002-07-01	14471
2002-10-01	14540
2003-01-01	15308
2003-04-01	15820
2003-07-01	15642
2003-10-01	15897
2004-01-01	16049
2004-04-01	15721
2004-07-01	16717
2004-10-01	17938
2005-01-01	17501
2005-04-01	17242
2005-07-01	17214
2005-10-01	16391
2006-01-01	16156
2006-04-01	17068
2006-07-01	17430
2006-10-01	17927
2007-01-01	19664
2007-04-01	20567
2007-07-01	20468
2007-10-01	21191
2008-01-01	21673
2008-04-01	22250
2008-07-01	22637
2008-10-01	22020
2009-01-01	21317
2009-04-01	21315
2009-07-01	22184
2009-10-01	23281
2010-01-01	24580
2010-04-01	22790
2010-07-01	26877
2010-10-01	29800
2011-01-01	32505
2011-04-01	36270
2011-07-01	36185
2011-10-01	37703
2012-01-01	40523
2012-04-01	40493
2012-07-01	42811
2012-10-01	44837
2013-01-01	48877
2013-04-01	47608
2013-07-01	50896
2013-10-01	52198
2014-01-01	53886
2014-04-01	55255
2014-07-01	55992
2014-10-01	56715
2015-01-01	58815
2015-04-01	64724
2015-07-01	61915
2015-10-01	60941
2016-01-01	63602
2016-04-01	63951
2016-07-01	63160
2016-10-01	61407
2017-01-01	62803
2017-04-01	63469
2017-07-01	65665
2017-10-01	65081
2018-01-01	64751
2018-04-01	63595