Quarter	Millions of US Dollars
1975-01-01	64
1975-04-01	198
1975-07-01	178
1975-10-01	180
1976-01-01	234
1976-04-01	251
1976-07-01	287
1976-10-01	324
1977-01-01	502
1977-04-01	759
1977-07-01	940
1977-10-01	1317
1978-01-01	1364
1978-04-01	1722
1978-07-01	1849
1978-10-01	1860
1979-01-01	1985
1979-04-01	2770
1979-07-01	2909
1979-10-01	3288
1980-01-01	3534
1980-04-01	4714
1980-07-01	5319
1980-10-01	5832
1981-01-01	5933
1981-04-01	5861
1981-07-01	5956
1981-10-01	6380
1982-01-01	6873
1982-04-01	6680
1982-07-01	6634
1982-10-01	7334
1983-01-01	8595
1983-04-01	8115
1983-07-01	8152
1983-10-01	9264
1984-01-01	9816
1984-04-01	11491
1984-07-01	12038
1984-10-01	13287
1985-01-01	11996
1985-04-01	14514
1985-07-01	14900
1985-10-01	14440
1986-01-01	14817
1986-04-01	15242
1986-07-01	15761
1986-10-01	15370
1987-01-01	16330
1987-04-01	15690
1987-07-01	15469
1987-10-01	16809
1988-01-01	17216
1988-04-01	14706
1988-07-01	14521
1988-10-01	14744
1989-01-01	14172
1989-04-01	13331
1989-07-01	13554
1989-10-01	13368
1990-01-01	13097
1990-04-01	11919
1990-07-01	12219
1990-10-01	12404
1991-01-01	11533
1991-04-01	11137
1991-07-01	11513
1991-10-01	10985
1992-01-01	10299
1992-04-01	11147
1992-07-01	10856
1992-10-01	11159
1993-01-01	14699
1993-04-01	14856
1993-07-01	32087
1993-10-01	33052
1994-01-01	36862
1994-04-01	44338
1994-07-01	48903
1994-10-01	50386
1995-01-01	53890
1995-04-01	57213
1995-07-01	57636
1995-10-01	55502
1996-01-01	55915
1996-04-01	60258
1996-07-01	57205
1996-10-01	56067
1997-01-01	52180
1997-04-01	53698
1997-07-01	52537
1997-10-01	47546
1998-01-01	43844
1998-04-01	45338
1998-07-01	44872
1998-10-01	42857
1999-01-01	35463
1999-04-01	32075
1999-07-01	31921
1999-10-01	29581
2000-01-01	26720
2000-04-01	25251
2000-07-01	22206
2000-10-01	21437
2001-01-01	19199
2001-04-01	18689
2001-07-01	18077
2001-10-01	17162
2002-01-01	16949
2002-04-01	19254
2002-07-01	17975
2002-10-01	18927
2003-01-01	17381
2003-04-01	16851
2003-07-01	17126
2003-10-01	17418
2004-01-01	16415
2004-04-01	15962
2004-07-01	15978
2004-10-01	17103
2005-01-01	18474
2005-04-01	17376
2005-07-01	17295
2005-10-01	16417
2006-01-01	17324
2006-04-01	18345
2006-07-01	18135
2006-10-01	18737
2007-01-01	17852
2007-04-01	19558
2007-07-01	18582
2007-10-01	20781
2008-01-01	17686
2008-04-01	17367
2008-07-01	15830
2008-10-01	14510
2009-01-01	18739
2009-04-01	28457
2009-07-01	34041
2009-10-01	33833
2010-01-01	35676
2010-04-01	28774
2010-07-01	30900
2010-10-01	38416
2011-01-01	34835
2011-04-01	34590
2011-07-01	31285
2011-10-01	35037
2012-01-01	32203
2012-04-01	33481
2012-07-01	34239
2012-10-01	45728
2013-01-01	55792
2013-04-01	53856
2013-07-01	58551
2013-10-01	59799
2014-01-01	60260
2014-04-01	64257
2014-07-01	65118
2014-10-01	74246
2015-01-01	66820
2015-04-01	59911
2015-07-01	62333
2015-10-01	66612
2016-01-01	59884
2016-04-01	54655
2016-07-01	56292
2016-10-01	57897
2017-01-01	57390
2017-04-01	56183
2017-07-01	58048
2017-10-01	55972
2018-01-01	58956
2018-04-01	54957