Quarter	Millions of US Dollars
1972-07-01	50
1972-10-01	50
1973-01-01	50
1973-04-01	50
1973-07-01	50
1973-10-01	50
1974-01-01	50
1974-04-01	50
1974-07-01	50
1974-10-01	50
1975-01-01	50
1975-04-01	92
1975-07-01	88
1975-10-01	88
1976-01-01	114
1976-04-01	114
1976-07-01	116
1976-10-01	117
1977-01-01	147
1977-04-01	148
1977-07-01	248
1977-10-01	300
1978-01-01	304
1978-04-01	301
1978-07-01	308
1978-10-01	315
1979-01-01	312
1979-04-01	313
1979-07-01	320
1979-10-01	321
1980-01-01	283
1980-04-01	344
1980-07-01	340
1980-10-01	332
1981-01-01	295
1981-04-01	242
1981-07-01	243
1981-10-01	244
1982-01-01	241
1982-04-01	241
1982-07-01	240
1982-10-01	242
1983-01-01	241
1983-04-01	239
1983-07-01	238
1983-10-01	237
1984-01-01	239
1984-04-01	236
1984-07-01	233
1984-10-01	272
1985-01-01	445
1985-04-01	396
1985-07-01	573
1985-10-01	505
1986-01-01	688
1986-04-01	958
1986-07-01	1054
1986-10-01	1117
1987-01-01	1431
1987-04-01	1423
1987-07-01	1438
1987-10-01	1877
1988-01-01	2162
1988-04-01	2048
1988-07-01	2235
1988-10-01	2631
1989-01-01	2887
1989-04-01	2863
1989-07-01	3213
1989-10-01	3423
1990-01-01	3580
1990-04-01	3767
1990-07-01	4212
1990-10-01	4691
1991-01-01	4462
1991-04-01	4416
1991-07-01	4761
1991-10-01	5987
1992-01-01	6154
1992-04-01	6563
1992-07-01	7153
1992-10-01	6571
1993-01-01	7975
1993-04-01	8733
1993-07-01	10145
1993-10-01	10213
1994-01-01	11726
1994-04-01	12324
1994-07-01	13053
1994-10-01	13653
1995-01-01	15036
1995-04-01	15907
1995-07-01	15345
1995-10-01	15695
1996-01-01	15183
1996-04-01	14716
1996-07-01	14066
1996-10-01	13311
1997-01-01	12503
1997-04-01	12718
1997-07-01	12170
1997-10-01	11355
1998-01-01	10797
1998-04-01	10685
1998-07-01	11269
1998-10-01	12151
1999-01-01	11360
1999-04-01	12312
1999-07-01	12437
1999-10-01	12376
2000-01-01	11379
2000-04-01	10751
2000-07-01	9925
2000-10-01	10228
2001-01-01	9700
2001-04-01	10458
2001-07-01	10990
2001-10-01	10053
2002-01-01	9465
2002-04-01	10213
2002-07-01	9892
2002-10-01	10302
2003-01-01	11058
2003-04-01	10702
2003-07-01	11370
2003-10-01	11892
2004-01-01	11348
2004-04-01	11968
2004-07-01	12857
2004-10-01	15480
2005-01-01	17551
2005-04-01	17614
2005-07-01	18276
2005-10-01	18136
2006-01-01	21948
2006-04-01	21623
2006-07-01	23752
2006-10-01	26564
2007-01-01	29571
2007-04-01	30670
2007-07-01	32067
2007-10-01	33032
2008-01-01	36564
2008-04-01	39784
2008-07-01	37058
2008-10-01	35914
2009-01-01	32689
2009-04-01	34278
2009-07-01	36975
2009-10-01	37797
2010-01-01	36758
2010-04-01	34445
2010-07-01	35829
2010-10-01	34807
2011-01-01	39094
2011-04-01	40075
2011-07-01	38384
2011-10-01	36061
2012-01-01	36722
2012-04-01	34769
2012-07-01	35811
2012-10-01	36000
2013-01-01	36451
2013-04-01	37197
2013-07-01	38580
2013-10-01	42124
2014-01-01	43687
2014-04-01	42761
2014-07-01	37760
2014-10-01	38697
2015-01-01	35274
2015-04-01	35879
2015-07-01	35850
2015-10-01	34862
2016-01-01	34714
2016-04-01	34573
2016-07-01	33014
2016-10-01	31773
2017-01-01	31947
2017-04-01	31204
2017-07-01	29968
2017-10-01	31092
2018-01-01	29440
2018-04-01	26885