Quarter	Millions of US Dollars
1968-04-01	15
1968-07-01	15
1968-10-01	15
1969-01-01	15
1969-04-01	15
1969-07-01	15
1969-10-01	15
1970-01-01	15
1970-04-01	15
1970-07-01	15
1970-10-01	15
1971-01-01	55
1971-04-01	95
1971-07-01	97
1971-10-01	99
1972-01-01	196
1972-04-01	299
1972-07-01	348
1972-10-01	390
1973-01-01	521
1973-04-01	642
1973-07-01	638
1973-10-01	617
1974-01-01	770
1974-04-01	797
1974-07-01	1053
1974-10-01	1259
1975-01-01	1915
1975-04-01	2444
1975-07-01	2607
1975-10-01	3163
1976-01-01	4034
1976-04-01	4942
1976-07-01	5557
1976-10-01	6237
1977-01-01	6659
1977-04-01	7038
1977-07-01	7371
1977-10-01	8639
1978-01-01	9336
1978-04-01	9851
1978-07-01	10972
1978-10-01	11009
1979-01-01	11263
1979-04-01	11946
1979-07-01	12842
1979-10-01	13225
1980-01-01	12386
1980-04-01	13778
1980-07-01	14039
1980-10-01	14491
1981-01-01	14790
1981-04-01	14423
1981-07-01	14864
1981-10-01	15851
1982-01-01	17138
1982-04-01	18446
1982-07-01	19986
1982-10-01	22104
1983-01-01	23662
1983-04-01	25200
1983-07-01	25584
1983-10-01	26881
1984-01-01	29202
1984-04-01	29321
1984-07-01	31167
1984-10-01	32155
1985-01-01	34251
1985-04-01	35018
1985-07-01	38664
1985-10-01	39353
1986-01-01	40712
1986-04-01	44244
1986-07-01	46841
1986-10-01	48656
1987-01-01	54855
1987-04-01	56697
1987-07-01	56860
1987-10-01	62489
1988-01-01	63403
1988-04-01	65014
1988-07-01	66858
1988-10-01	72290
1989-01-01	73048
1989-04-01	73295
1989-07-01	77743
1989-10-01	79897
1990-01-01	81855
1990-04-01	85901
1990-07-01	94815
1990-10-01	98443
1991-01-01	95301
1991-04-01	98548
1991-07-01	105354
1991-10-01	115783
1992-01-01	114468
1992-04-01	122410
1992-07-01	130234
1992-10-01	123510
1993-01-01	125007
1993-04-01	125363
1993-07-01	131404
1993-10-01	131158
1994-01-01	138133
1994-04-01	142414
1994-07-01	148477
1994-10-01	149831
1995-01-01	160868
1995-04-01	161340
1995-07-01	159848
1995-10-01	162377
1996-01-01	160084
1996-04-01	166447
1996-07-01	169203
1996-10-01	167906
1997-01-01	165897
1997-04-01	163151
1997-07-01	165872
1997-10-01	165250
1998-01-01	172935
1998-04-01	178547
1998-07-01	196889
1998-10-01	204164
1999-01-01	206273
1999-04-01	213944
1999-07-01	234888
1999-10-01	239730
2000-01-01	245613
2000-04-01	257399
2000-07-01	262139
2000-10-01	287407
2001-01-01	308376
2001-04-01	315345
2001-07-01	351267
2001-10-01	364770
2002-01-01	366094
2002-04-01	429400
2002-07-01	433345
2002-10-01	476147
2003-01-01	510771
2003-04-01	571263
2003-07-01	604696
2003-10-01	678439
2004-01-01	681180
2004-04-01	710413
2004-07-01	745543
2004-10-01	850734
2005-01-01	855888
2005-04-01	854047
2005-07-01	856240
2005-10-01	882266
2006-01-01	937929
2006-04-01	1010377
2006-07-01	1039667
2006-10-01	1158097
2007-01-01	1199617
2007-04-01	1299517
2007-07-01	1355585
2007-10-01	1438960
2008-01-01	1545634
2008-04-01	1641101
2008-07-01	1527738
2008-10-01	1477833
2009-01-01	1436863
2009-04-01	1621604
2009-07-01	1690460
2009-10-01	1700631
2010-01-01	1667755
2010-04-01	1547846
2010-07-01	1721123
2010-10-01	1713609
2011-01-01	1895960
2011-04-01	1941682
2011-07-01	1817576
2011-10-01	1766308
2012-01-01	1847505
2012-04-01	1741214
2012-07-01	1790529
2012-10-01	1807750
2013-01-01	1763638
2013-04-01	1792752
2013-07-01	1836140
2013-10-01	1848081
2014-01-01	1879684
2014-04-01	1878260
2014-07-01	1765879
2014-10-01	1686598
2015-01-01	1547777
2015-04-01	1565546
2015-07-01	1538174
2015-10-01	1498587
2016-01-01	1543980
2016-04-01	1537053
2016-07-01	1555241
2016-10-01	1504643
2017-01-01	1532293
2017-04-01	1600300
2017-07-01	1637832
2017-10-01	1670336
2018-01-01	1699459
2018-04-01	1644503