Quarter	Millions of US Dollars
1966-01-01	20
1966-04-01	20
1966-07-01	20
1966-10-01	20
1967-01-01	20
1967-04-01	20
1967-07-01	20
1967-10-01	35
1968-01-01	35
1968-04-01	35
1968-07-01	35
1968-10-01	35
1969-01-01	35
1969-04-01	35
1969-07-01	35
1969-10-01	35
1970-01-01	35
1970-04-01	35
1970-07-01	35
1970-10-01	35
1971-01-01	80
1971-04-01	101
1971-07-01	118
1971-10-01	118
1972-01-01	239
1972-04-01	271
1972-07-01	293
1972-10-01	360
1973-01-01	461
1973-04-01	541
1973-07-01	538
1973-10-01	553
1974-01-01	597
1974-04-01	645
1974-07-01	651
1974-10-01	769
1975-01-01	1097
1975-04-01	1475
1975-07-01	1446
1975-10-01	1809
1976-01-01	2160
1976-04-01	2333
1976-07-01	2659
1976-10-01	3127
1977-01-01	3414
1977-04-01	3843
1977-07-01	4232
1977-10-01	5004
1978-01-01	5319
1978-04-01	5753
1978-07-01	6280
1978-10-01	6343
1979-01-01	6442
1979-04-01	7315
1979-07-01	7617
1979-10-01	7923
1980-01-01	7907
1980-04-01	9357
1980-07-01	9946
1980-10-01	10215
1981-01-01	10362
1981-04-01	10137
1981-07-01	10398
1981-10-01	11144
1982-01-01	11845
1982-04-01	11627
1982-07-01	11805
1982-10-01	12783
1983-01-01	14447
1983-04-01	13937
1983-07-01	13883
1983-10-01	14872
1984-01-01	15715
1984-04-01	17281
1984-07-01	17805
1984-10-01	19289
1985-01-01	18172
1985-04-01	21076
1985-07-01	22115
1985-10-01	21390
1986-01-01	22943
1986-04-01	24470
1986-07-01	25969
1986-10-01	25896
1987-01-01	30632
1987-04-01	31427
1987-07-01	31660
1987-10-01	33691
1988-01-01	35115
1988-04-01	34329
1988-07-01	34365
1988-10-01	35433
1989-01-01	36739
1989-04-01	36025
1989-07-01	37554
1989-10-01	39411
1990-01-01	41306
1990-04-01	42464
1990-07-01	46338
1990-10-01	45668
1991-01-01	42796
1991-04-01	42012
1991-07-01	44412
1991-10-01	44917
1992-01-01	43012
1992-04-01	47028
1992-07-01	51089
1992-10-01	51505
1993-01-01	55624
1993-04-01	64933
1993-07-01	69272
1993-10-01	71750
1994-01-01	78973
1994-04-01	87698
1994-07-01	93167
1994-10-01	94424
1995-01-01	98985
1995-04-01	100948
1995-07-01	100943
1995-10-01	98813
1996-01-01	100971
1996-04-01	104951
1996-07-01	103617
1996-10-01	103159
1997-01-01	99755
1997-04-01	102241
1997-07-01	100857
1997-10-01	96013
1998-01-01	90794
1998-04-01	93697
1998-07-01	93833
1998-10-01	92850
1999-01-01	84296
1999-04-01	86835
1999-07-01	91406
1999-10-01	90487
2000-01-01	92219
2000-04-01	90742
2000-07-01	87207
2000-10-01	88394
2001-01-01	85033
2001-04-01	86128
2001-07-01	87063
2001-10-01	84929
2002-01-01	84502
2002-04-01	96788
2002-07-01	97536
2002-10-01	99350
2003-01-01	103153
2003-04-01	108745
2003-07-01	110825
2003-10-01	119480
2004-01-01	124082
2004-04-01	122037
2004-07-01	126868
2004-10-01	136828
2005-01-01	138796
2005-04-01	146256
2005-07-01	148343
2005-10-01	146277
2006-01-01	160700
2006-04-01	167471
2006-07-01	166995
2006-10-01	183386
2007-01-01	200252
2007-04-01	223208
2007-07-01	230427
2007-10-01	246650
2008-01-01	258861
2008-04-01	281660
2008-07-01	279756
2008-10-01	261769
2009-01-01	275861
2009-04-01	322178
2009-07-01	354789
2009-10-01	361013
2010-01-01	374691
2010-04-01	344946
2010-07-01	374628
2010-10-01	380107
2011-01-01	398402
2011-04-01	416874
2011-07-01	405378
2011-10-01	396966
2012-01-01	423584
2012-04-01	421004
2012-07-01	441080
2012-10-01	462722
2013-01-01	469072
2013-04-01	472538
2013-07-01	501394
2013-10-01	497186
2014-01-01	498014
2014-04-01	502360
2014-07-01	482004
2014-10-01	477791
2015-01-01	446862
2015-04-01	458979
2015-07-01	462857
2015-10-01	465983
2016-01-01	478927
2016-04-01	464501
2016-07-01	468139
2016-10-01	458032
2017-01-01	475651
2017-04-01	495639
2017-07-01	506587
2017-10-01	505763
2018-01-01	518488
2018-04-01	501255