Quarter	Millions of US Dollars
1968-07-01	40
1968-10-01	40
1969-01-01	40
1969-04-01	40
1969-07-01	40
1969-10-01	40
1970-01-01	40
1970-04-01	40
1970-07-01	40
1970-10-01	40
1971-01-01	40
1971-04-01	40
1971-07-01	40
1971-10-01	40
1972-01-01	40
1972-04-01	65
1972-07-01	65
1972-10-01	115
1973-01-01	148
1973-04-01	193
1973-07-01	194
1973-10-01	206
1974-01-01	277
1974-04-01	293
1974-07-01	291
1974-10-01	320
1975-01-01	368
1975-04-01	367
1975-07-01	354
1975-10-01	374
1976-01-01	378
1976-04-01	391
1976-07-01	795
1976-10-01	849
1977-01-01	935
1977-04-01	977
1977-07-01	1067
1977-10-01	1145
1978-01-01	1352
1978-04-01	1517
1978-07-01	1708
1978-10-01	1848
1979-01-01	2066
1979-04-01	2162
1979-07-01	2400
1979-10-01	2362
1980-01-01	2263
1980-04-01	2458
1980-07-01	2605
1980-10-01	2634
1981-01-01	2563
1981-04-01	2508
1981-07-01	2618
1981-10-01	2848
1982-01-01	3140
1982-04-01	3373
1982-07-01	3347
1982-10-01	4012
1983-01-01	4027
1983-04-01	4243
1983-07-01	5588
1983-10-01	5766
1984-01-01	6260
1984-04-01	6162
1984-07-01	6430
1984-10-01	7428
1985-01-01	8186
1985-04-01	9759
1985-07-01	10991
1985-10-01	13405
1986-01-01	15284
1986-04-01	16453
1986-07-01	17134
1986-10-01	17301
1987-01-01	19535
1987-04-01	19760
1987-07-01	20061
1987-10-01	22572
1988-01-01	22256
1988-04-01	21208
1988-07-01	21820
1988-10-01	23069
1989-01-01	22218
1989-04-01	21536
1989-07-01	21713
1989-10-01	22385
1990-01-01	22184
1990-04-01	22834
1990-07-01	24523
1990-10-01	24821
1991-01-01	24825
1991-04-01	26439
1991-07-01	27867
1991-10-01	29480
1992-01-01	28704
1992-04-01	30103
1992-07-01	32623
1992-10-01	34544
1993-01-01	36175
1993-04-01	38136
1993-07-01	45078
1993-10-01	49671
1994-01-01	55490
1994-04-01	60402
1994-07-01	65299
1994-10-01	66932
1995-01-01	70934
1995-04-01	73460
1995-07-01	76652
1995-10-01	78549
1996-01-01	83441
1996-04-01	89958
1996-07-01	101369
1996-10-01	115043
1997-01-01	121617
1997-04-01	135267
1997-07-01	144352
1997-10-01	145833
1998-01-01	144879
1998-04-01	150227
1998-07-01	147720
1998-10-01	150091
1999-01-01	148667
1999-04-01	148371
1999-07-01	147901
1999-10-01	147516
2000-01-01	150030
2000-04-01	147954
2000-07-01	145421
2000-10-01	145104
2001-01-01	140186
2001-04-01	141484
2001-07-01	139410
2001-10-01	139340
2002-01-01	142108
2002-04-01	150592
2002-07-01	154436
2002-10-01	158661
2003-01-01	160224
2003-04-01	165552
2003-07-01	173487
2003-10-01	181832
2004-01-01	190629
2004-04-01	196491
2004-07-01	203416
2004-10-01	216696
2005-01-01	224661
2005-04-01	230226
2005-07-01	234629
2005-10-01	244278
2006-01-01	256869
2006-04-01	267358
2006-07-01	278509
2006-10-01	291261
2007-01-01	307779
2007-04-01	328253
2007-07-01	331983
2007-10-01	340040
2008-01-01	348940
2008-04-01	354579
2008-07-01	355172
2008-10-01	343600
2009-01-01	342403
2009-04-01	355094
2009-07-01	372718
2009-10-01	376959
2010-01-01	382966
2010-04-01	388191
2010-07-01	408741
2010-10-01	436298
2011-01-01	459409
2011-04-01	494877
2011-07-01	503705
2011-10-01	513167
2012-01-01	546684
2012-04-01	578151
2012-07-01	603631
2012-10-01	624915
2013-01-01	654377
2013-04-01	699150
2013-07-01	731739
2013-10-01	780991
2014-01-01	824974
2014-04-01	889878
2014-07-01	920936
2014-10-01	982145
2015-01-01	1005604
2015-04-01	1061598
2015-07-01	1069390
2015-10-01	1098104
2016-01-01	1104161
2016-04-01	1148125
2016-07-01	1190737
2016-10-01	1219203
2017-01-01	1293796
2017-04-01	1361559
2017-07-01	1439505
2017-10-01	1533849
2018-01-01	1599737
2018-04-01	1624604